Giant Revive BBS02 Mid-Drive

[LewTwo]

This is the actual build thread for my Giant Revive with a Bafang BBS02 Mid Drive. There are two other threads you might also want to look at:

1) This is the thread I first started when considering purchasing this bike/frame and the feasibility of installing a mid-drive motor.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=117000

2) This is Cowardlyduck's thread that references several Revive build threads
https://endless-sphere.com/forums/viewtopic.php?f=6&t=114664

First I want to start with documenting the Giant Revive Bicycle as I received it. This picture was taken the day after it was purchased:
These are the OEM dimensions near as I can determine (message me if you want the CAD file):



In Cowardlyduck's thread there is a XLS file with the OEM Specifications as near as I could determine them:

The serial number for the frame is located on the non-drive side rear drop out. It was very hard to read and required a bit of enhancement to reveal the characters on either end:
G = Giant Brand
E = Fortnight frame was built
3 = Year frame was built, in this case 2003 as Giant discontinued the Revive line in 2012.
D = According to some folks this is supposed to be a number, however all the Revives serial numbers that I have found have a "D" here
1693 = actual serial number
I checked the National Bicycle Registry for stolen bikes and this serial number was not found. Giant have several versions including "Revive", "Revive DX" and "Revive LX". The latter two had a much different swing arm. I believe that there was also an electrified version on offer at one time.

First Problems:
1) Remove warped rear fender. Cheap plastic parts do not fair well in Hot Southern Texas temperatures.
2) 20x1.75 tires are tiny. Rear tire has already been replaced with 20x2.25 tire.
3) OEM 600 pound/inch spring is sized for a 300 pound sumo wrestler. It has already been replaced with a FOX 300 pound/inch spring. MAJOR IMPROVEMENT !!!

Target Environment:
This will be ridden almost exclusively on street pavements but in Houston that is not saying much. Target speed is 20 to 25 MPH on throttle with a 135 pound operator on flat pavement. Cargo option is to be a Travoy trailer hitched to the rear rack.

Tentative Plans:
1. BBS02 750 Watt mid-drive, 48 tooth sprocket and 52 Volt battery
2. front air suspension fork, Pasak P70
3. 20 x 34 mm alloy rims (3 spoke 'mag style' wheels)
4. 20 x 2.25 wide tires
5. Tannus Armour Tire Inserts
6. Rear Hub, Retain 8 speed Hyper Cassette and Derailleur
7. Brakes: Disks, Avid 7, Rotors ? Also going to need a rear caliper mount
8. rear air shock ??
9. Gates Belt Drive ???

 

[LewTwo]

WHEELS

The idea that I am going to pedal much is absurd. The pedals are there to rest my feet on and to keep it legal. I am going to take a shot at running a single fixed gear ratio ... less stuff to go wrong, go wrong, go wrong ...

The wheels that came on the Revive are some what less than optimal. I call them 'TOY' rims. I want to run 20x2.25 tires that actually measure about 55 mm wide. That is 'balloon' tire territory as opposed to 'fat' tire. The recommended inner rim width is 24 mm. I found a set of used Aluminum BMX rims on ebay: 30 mm outer width, 24 mm inner width. The good news is no messing with shifters, spoke tension, broken spokes, wheel alignment, etc. Of course they are 'old school' which means I am keeping the cantilever brakes. It also means the rims (aka large diameter disks) will eventually wear out but I am an old fart so they may outlast me.

For reference: that is a 20x2.10 tire mounted on the front rim.

According to my calculations that 16 tooth freewheel and a 48 tooth crank sprocket should get me a top speed of 20 MPH. I need to find a replacement 12 tooth freewheel (what I know about BMX hubs would fill the top of a pin-head in large print).

Edit Update:
According to the USPS, last seen in NJ processing center about a week ago :lol: :lol: :lol:
Thanks to the USPS my purchase costs were refunded.

 

[Chalo]

Cast rims are hookless, so you can't inflate all the way to the tire's pressure rating without risking a blow-off. Certainly don't exceed 60psi no matter what the tire says.

 

[LewTwo]

Cast rims are hookless, so you can't inflate all the way to the tire's pressure rating without risking a blow-off. Certainly don't exceed 60psi no matter what the tire says.

Did not know that ... thank thee.
I was really thinking something closer to 30 PSI.
When I blew that tire off the Revive rim, I was more or less trying to find its limits.

What do you think of the idea single speed drive (for an individual a bit lighter than yourself)?

 

[PaPaSteve]

An article explaining the different rims for bicycles and what tires should be used on each design.
https://www.gravelcyclist.com/bicycle-tech/the-hookless-bead-rim-how-it-works-who-theyre-for-by-enve-composites/

 

[LewTwo]

An article explaining the different rims for bicycles and what tires should be used on each design.
https://www.gravelcyclist.com/bicycle-tech/the-hookless-bead-rim-how-it-works-who-theyre-for-by-enve-composites/

Well I read that story and did some other research on line. It seems that tubeless tires are another bicycle marketing boondoggle by a couple of companies without any industry standardization. They are ONLY available in a limited number of sizes and the theoretical advantages do not seem to have been proven in real life applications. They are also labor intensive to install and maintain (much like sew-up tubular tires). They may have a tad more market share than solid foam rubber tires.

Manufactures could produce "hooked" cast rims but it would require extra machining of the finished product. I believe that "hookless" cast rims are more likely the result of manufacturing engineers cutting corners to reduce costs without any concern for the quality of their products (a far too common occurrence).

 

[BalorNG]

An article explaining the different rims for bicycles and what tires should be used on each design.
https://www.gravelcyclist.com/bicycle-tech/the-hookless-bead-rim-how-it-works-who-theyre-for-by-enve-composites/

Well I read that story and did some other research on line. It seems that tubeless tires are another bicycle marketing boondoggle by a couple of companies without any industry standardization. They are ONLY available in a limited number of sizes and the theoretical advantages do not seem to have been proven in real life applications. They are also labor intensive to install and maintain (much like sew-up tubular tires). They may have a tad more market share than solid foam rubber tires.

Manufactures could produce "hooked" cast rims but it would require extra machining of the finished product. I believe that "hookless" cast rims are more likely the result of manufacturing engineers cutting corners to reduce costs without any concern for the quality of their products (a far too common occurrence).

No, no and no. But than, latex tubes with sealant do allow one to reap about 90% of tubeless tire benefits.

 

[LewTwo]

I ordered the Pasak P70 Air fork. I usually do not favor putting a suspension fork on a bicycle that was not designed for that in the first place because it changes the geometry. In this case I consider that change to be an improvement. However this fork ONLY supports disk brakes. Well I wanted a disk brake in front anyway.

Sometimes one needs to acknowledge their mistakes and move on.
The used Rebel rims are a mistake. No bead hooks, 110 mm OLD rear hub, black, no disk support.
Some of these problems have possible solutions but at a cost and possibly more trouble than value.

Moving on:
I ordered a set of spoke rims via EBAY
Very importantly these rims have bead hooks (25 mm inside channel). Both front and rear rims have sealed bearings and skewers (I actually prefer solid nutted axles). The rear wheel has a cassette hub (I would have preferred a free wheel) with an 135 mm OLD. So I can retain the original 8 speed hyperglide cassette and derailleur until I convert it to single speed. They also "claim" to be "Powder coated Magnesium-Titanium Alloy" and "Rim Brake compatible". So in theory I can retain the cantilever brake on the rear ... however I am not totally comfortable with trying rub the white paint off the rim with the cantilever brake pads.

The Tannus Armour Tire Inserts are '20 x 1.95 to 2.5' so they will require a wee bit of trimming for the 20 x 2.25 tires.

 

[LewTwo]

IT FITS !!!
I did have to get out my cheapo electric die grinder and make a small notch in one side of the swingarm pivot bracket. I have one short cable (yellow 3 pin) from the BBS02B motor that has nothing to connect to it (gear change sensor?). It will need to be capped somehow.

I do have to relocate the rear brake cable (and the motor cables) above the BB instead of below it. In order to do that I had to enlarge the opening above the pivot point a bit. That white thing is a bit of de-cored pararcord used to fish the cables and wires through the frame. The speedometer cable is about 6 inches short. Had to order an extension for that. Will also have to drill/tap one of the spokes to mount the magnet. I am now waiting for brake cables and pieces parts.

I am going to try to use the standard Bafang Brake levers as they came with the kit and incorporate the appropriate switches. I have decided to use Shimano stainless steel brake cables as they are inexpensive and are 1.6 mm (vs 1.5 mm in diameter).

 

[PaPaSteve]

 

[LewTwo]

Well I finally got the 20 x 2.25 tires mounted on the new rims with the Tannus Amour inserts and tubes. Took me more than four hours to get the first one mounted. I recommend delegating this task to someone with four arms and six hands (and an unlimited supply of tire levers as one might lose a few when they go flying across horizon).

Tannus instructions for installing the inserts do not work for wheels this small. These do work but only with a lot of work:

1. Trim about 1/4 inch from each edge of the insert. Otherwise you will never get the valve stem through the rim.
2. Stuff Tannus Amour insert into tire (helps to warm it up in the sun).
3. Stuff Tannus Amour tube into insert.
4. Stuff rim into tire … that means one bead outside each side of the rim.
5. Stuff tube and insert edges into rim recess … they will not want to stay there.
6. Seat bead for one side of tire into the rim … use multiple tire levers and extra hands.
7. Seat the bead for opposite side of tire into the rim … use multiple tire levers and extra hands.
8. Now reseat the first bead because you accidentally pushed it out while working on the second bead.
9. Inflate to 5 PSI and leave overnight. This is to let everything shape to the rim.
10. Deflate tire. Carefully check beads to make sure that they seated and centered. Inflate to 25 PSI and let set overnight again.
11. Check tire pressure to insure that there are no leaks.

Having taken several days to do this, I was really proud to have gotten done. Then I noticed that these tires have a directional thread design and I had installed the front one back-asswards (big dummy). Pulling it off was only a little easier than mounting it, however it does go on a bit better after everything has taken a ‘set’.

Bad news is:
Wire spoke rims adsorb some shock. These do not … that has to be done by the tires.
The new rims and tires will add a bit of weight to the bike (about 2-1/2 pounds).
. Old front wheel assembly weight: 1.710 Kg (3.770 pounds)
. New front wheel assembly weight: 2.280 Kg (5.027 Pounds)
(with skewers but not including brake disk)

Good News is:
These wheel assemblies should require little if any maintenance and can ‘run flat’ if needed.

New front wheel assembly circumference: 161.0 cm (63.39 inches)
Actual Tire diameter: 51.24 cm (20.176 inches)
Measured fully inflated tire width: 52 mm (2.047 inches)

I might use the old wheels to build a trailer

Edit update:
Cheap plastic fender does not fit over larger front tire ... gone.

Still waiting on disk brake bits and pieces ….

 

[99t4]

Then I noticed that these tires have a directional thread design and I had installed the front one back-asswards (big dummy).

Probably you would have been allright with it "wrong-directioned. I have also done that inadvertently and was hard to notice a difference in riding performance. What is the significance of a directional tread tire on a bicycle anyway?

 

[LewTwo]

What is the significance of a directional tread tire on a bicycle anyway?

Normally the groves in the tread should be oriented to push water away from the center of the tire with a forward rotation. 'Tis valid for bicycles, motorcycles, cars and other motor vehicles. I run 'Thick Slicks' on my road bike frame and they have no grooves/tread pattern.

 

[LewTwo]

I wanted to swap out the hollow axles that came with the 'mag' spoke wheels for solid ones. Most of the US vendors do not have anything in the correct length or what they do have is only for cone-nut bearings. The Chinese vendors are for the most part are totally clueless about what they have on offer (never having every physically seen anything that they are selling). The few vendors that do offer a solid axle kit (that looks almost right) all seem to source a single manufacturer in China. Previous purchasers report that they have undersized bearing seat diameters and use an inferior, soft axle material.

So it looks like I am stuck with the "Bar-B-Que skewer" hollow axles unless I prepare new drawings and have a local machine shop fabricate them
The attached ZIP file contains the original DWG, DXF, SVG and vector PDF files.

PUBLIC DOMAIN:
The files attached to this message post on Endless Sphere are the original work product of the author, Lewis Balentine, Houston, Texas. The author freely releases these files to the public domain, August 2022.

DISCLAIMER:
There is no warranty, expressed or implied, regards the accuracy or fitness of the attached files for any purpose. The author assumes no responsibility for the accuracy and/or information in these files.

Original DWG file created with ARES Commander

 

[Chalo]

Quick release axles are more secure than nutted axles, because the QR skewers have more elastic range than the short section of axle that's placed under tension by an axle nut.

Most QR rear axles are 10mm in diameter, rather than the 9.5mm diameter of most threaded axles. That makes them slightly stiffer and stronger despite being hollow.

There's nothing better enough about solid axles to make me want to switch to them when I have quick release axles. You can use bolted skewers or keyed security skewers if you want a measure of theft resistance.

 

[LewTwo]

Quick release axles are more secure than nutted axles, because the QR skewers have more elastic range than the short section of axle that's placed under tension by an axle nut.

Most QR rear axles are 10mm in diameter, rather than the 9.5mm diameter of most threaded axles. That makes them slightly stiffer and stronger despite being hollow.

There's nothing better enough about solid axles to make me want to switch to them when I have quick release axles. You can use bolted skewers or keyed security skewers if you want a measure of theft resistance.

Partly it has to do with how I wanted to fabricate a rear disk brake adapter. I wanted a plate on the outboard side of the non-drive side dropout. It would be partially secured in place by the M10 axle, the axle nuts.

I agree that with all other things being equal, a 5mm skewer is more elastic than 10mm high strength axle bolt under the same tension. However I question the validity of that being a good thing. If the question is of it being adequate under ideal conditions then the answer is "yes". I was taught to consider the worse case scenario as well as the ideal scenario. That lesson has been well entrenched in my though processes.

With the skewer design one is dependent on the frictional resistance between the surfaces of the 19 mm axle nuts and dropout on each side (two planes). Loose any of the tension in the skewer and one losses the resistance in both planes. The back-up is the shear strength of the narrow 4 mm and 5 mm hollow axle ledges inside the dropouts.

With a solid nutted axle, one has two similar friction connections on each axle. Loose the tension in any single connection and one still has the probability of one apropos connection on that axle. The back-up is the shear strength of the 10 mm axle inside the full width of the dropouts.

As far as "theft resistance" is concerned, I favor suitable cable locks and 12 gauge shotgun loaded with heavy slugs. Unfortunately there are certain legal ramifications to the latter.

 

[LewTwo]

So the rear disk caliper adapter that I got from China (although the FleaBay vendor listed it as being located in New Jersey) is one of the worst POS parts that I have seen come out of SEA. The holes drilled in the steel plate did not match the threaded holes in the Aluminum Bracket. The 2 mm thick steel plate was so weak I could bend it by hand. The space between the steel plate and aluminum bracket was 5 mm but the anvil piece between the two plates was 6.5 mm thick. The two legs of the aluminum bracket were different widths and not parallel to each other. Piss poor design and worse manufacturing.

Back to building my own adapter. I do not have access to a milling machine so I have come up with a scheme to use two pieces of 5/16 inch thick aluminum plate. The concept is to glue a 1:1 print to the surface of the aluminum and use a jig saw to cut out a rough outline of the part. Then use grinder and files to produce the desired final desired shape. The smaller bit needs to made to "fit" the dropout anyway.

EDIT UPDATE (28 Aug 2022): Graphic Replaced with New Design


The idea is to mount this adapter to the inside face of the dropout (which just happens to be about 5/16 inch thick).

 

[PaPaSteve]

Suggesting

https://sendcutsend.com/

Quick turn around, precision made to your drawing, $30 minimum order.

 

[LewTwo]

Suggesting

https://sendcutsend.com/

Quick turn around, precision made to your drawing, $30 minimum order.

Thank you Papa. I will look into that but it would require going from 5/16 to 1/4 thick plates and a bit different thought process.

EDIT UPDATE (28 Aug 2022): Graphic Removed

I would need the additional "washer" so that I can use a M10 bolt, nut and fender washer to secure the adapter plate to the dropout for "trial fit up". Then scribe the exact outline of the drop out slot ... my drawing is only as close as I can get it (i.e. best guess) from a picture using a somewhat distorted closeup camera lens.

 

[PaPaSteve]

Before sending something like this out for Laser cutting verify the dimensions are correct by printing it out with your home printer on card stock. Cut with scissors or utility knife then fit check. If needed stack and glue several layers together.

sendcutsend is a resource I use on occasion whenever it makes sense.
Sometimes several sets can be made within their minimum fee.

I have experience running metal cutting lasers and waterjets but don't own either.

 

[LewTwo]

Before sending something like this out for Laser cutting verify the dimensions are correct by printing it out with your home printer on card stock. Cut with scissors or utility knife then fit check. If needed stack and glue several layers together.

Good advice as usual, but my ink-jet printer does not have a paper path for card stock ... so I used standard 20 pound bond. I started at the beginning ... the dropout. I must have cut out over two dozen paper templates until I got one that I felt was 'close enough for government work'. I was reminded of a small child playing with paper dolls (do they still have those).

I changed the design (see above). The back plate (Part "A" mounted on the inside face of the left rear dropout) is going to be 1/4 inch thick 316 stainless steel. It just happens to get all the M6 thread holes. I still plan on match drilling the three holes in the dropout at fit-up. Giant did not bother to drill the fender mount holes 'on center' when they manufactured the bike and it is important that they are located correctly relative to the center of the rear axle. Fortunately 5.0 mm just happens to be the correct hole size for a M6-1 tap

I decide to use a sandwich of 1/4 and 1/16 pieces (Part "B") so that the adapter matches the width of the dropout. I ordered the 1/16 plates in both Aluminum and Stainless Steel. I am considering making the outside SST for appearance sake.

I changed the fasteners to all be M6-1 Stainless Steel Buttonhead screws (although for fit-up I will use Steel Hex Socket Head screws to reduce the chance of galling). I am still toying with the idea of using System Three T-88 epoxy for the final assembly but with three M6 screws through the dropout that might be overkill.

I also ordered some extra 'fit-up' washers as those could come in handy for mounting a M10 axle(s) in my pick-em-up bed for transport.

Now I need to go order a set of metric drills bits ... Imperial is not close enough for this.

P.S.
It occurs to me that adding a toque plate for a rear hub motor would be a fairly simple addition to this design.

 

[PaPaSteve]

Good to hear ...
Going back to your laser question.
I do have a small laser.
40 watts CO2 ... which isn't the correct wave length or enough power for metal cutting.
Great for making proof of concept parts.

 

[Excaliburke]

Really exciting stuff here, folks! I love the detailed technical drawings. Currently I'm agonizing over how to get more suspension on my Revive build. I have a zany idea to add a suspension fork to the front (probably 335mm axle to crown) compensated by installing a longer shock in the rear to hopefully retain the same steering geometry. However, I'm a bit stuck on the maths, and I don't quite have a successful track record in altering bike geometry. My last project was a complete failure in that regard. Will be following this thread intently.

 

[LewTwo]

I have a zany idea to add a suspension fork to the front (probably 335mm axle to crown) compensated by installing a longer shock in the rear to hopefully retain the same steering geometry. However, I'm a bit stuck on the maths, and I don't quite have a successful track record in altering bike geometry. My last project was a complete failure in that regard. Will be following this thread intently.

The only air fork I could find for a 20 inch wheel is 395 mm axle to crown.

That length of 335 mm seems a bit short even for a spring fork.
The stock rigid fork is 310 mm. Just for simplicity ignore the offset.
If you use a 335 mm fork that will raise the front by 25 mm over a wheel base of 1230 mm.
That changes the angle by about 1.25 degrees.

The stock rear shock absorber is 165 mm long with about 38 mm of compression over a distance of about 395 mm.
The next standard size up is 190 mm long with a compression of 51 mm. A difference of about 25mm ... but over a much shorter distance. That changes the angle of the main seat tube by 3.75 degrees. So the seat actually winds up leaning further forward by about 2.5 degrees.

Note this is just a quick estimate without a precise layout. The other thing to note is that it raises the front end by 1 inch and the back end by about 2 inches.

I prefer to lean further backwards (hey, I am lazy) so at some point I will likely install a standard SR Suntour Raidon 160 mm airshock but I have to figure out what to do about bushings and pivot pins first.

 

[Excaliburke]

I have a zany idea to add a suspension fork to the front (probably 335mm axle to crown) compensated by installing a longer shock in the rear to hopefully retain the same steering geometry. However, I'm a bit stuck on the maths, and I don't quite have a successful track record in altering bike geometry. My last project was a complete failure in that regard. Will be following this thread intently.

The only air fork I could find for a 20 inch wheel is 395 mm axle to crown.

That length of 335 mm seems a bit short even for a spring fork.
The stock rigid fork is 310 mm. Just for simplicity ignore the offset.
If you use a 335 mm fork that will raise the front by 25 mm over a wheel base of 1230 mm.
That changes the angle by about 1.25 degrees.

The stock rear shock absorber is 165 mm long with about 38 mm of compression over a distance of about 395 mm.
The next standard size up is 190 mm long with a compression of 51 mm. A difference of about 25mm ... but over a much shorter distance. That changes the angle of the main seat tube by 3.75 degrees. So the seat actually winds up leaning further forward by about 2.5 degrees.

Note this is just a quick estimate without a precise layout. The other thing to note is that it raises the front end by 1 inch and the back end by about 2 inches.

I prefer to lean further backwards (hey, I am lazy) so at some point I will likely install a standard SR Suntour Raidon 160 mm airshock but I have to figure out what to do about bushings and pivot pins first.

Wow, this is impressive! I had no idea it leaned *forward*. Out of curiosity, is it possible to use the shock to compensate for a 395mm fork in some way? No idea what your plan is other than than the Raidon, but definitely post it up here when you get the bushing situation figured out.