Bought a Specialized Hardrock 29er Comp. Hub vs midrive?

[RoadWrinkle]

Now that I am using my new Motiv eCruiser with much satisfaction (it is a hill climbing machine), the e-biking hook has been set well and I now want to build something else for flatter, longer rides and more top end speed. I want to go with a 1000w rear mount DD hub motor, and a 48v 10-12 Ah LifePO4 battery mounted in triangle bag, and a good controller mounted under the downtube. I also like the new Bafang 750w 48v 25A crank drive systems incorporated into the BB, a very clean looking system. I originally created this thread to decide which donor to buy.I bought the Specialized Rockhopper 29er Comp

Now interested in advice on the e-components, a front hubmotor would be the easiest in terms of install, but then I would have an unmatched wheel on the front and perhaps issues with the Rockshock (TA's, etc.) Rear mount hubmotor means no 10-speed rear cassette and again mismatched wheels. I Contacted Holmes Hobbie re sending the OEM wheel for hub motor lace/install (received no response after three days). Midmount would solve the above issues but I would lose the 3-speed front derailleur completely and Bafang system is a 68mm BB design, where I have a 73 mm BB on the Rockhopper, so 5mm spacing and chain line offset necessary.


Specs for Rockhopper:
FRAME: Specialized A1 Premium Aluminum, Trail 29er Geometry, fully butted w/ tapered headtube, forged dropouts, replaceable alloy derailleur hanger SWAT REAR SHOCK
FORK: RockShox XC28 29, TurnKey damping w/ lockout, coil spring, 1-1/8" alloy steerer, 28mm stanchion, preload and rebound adj., S: 80mm, Others: 100mm travel HEADSET1-1/8" w/ lower bearing reducer, Campy style, integrated full cartridge bearings
STEM: Specialized 3D forged alloy, 4-bolt clamp, 6-degree rise, 31.8mm
FRONT BRAKE: Tektro Draco 2, hydraulic disc, dual piston, 180mm rotor
REAR BRAKE: Tektro Draco 2, hydraulic disc, dual piston, 160mm rotor
FRONT DERAILLEUR:SRAM X5, 10-speed 2X10, 34.9mm clamp
REAR DERAILLEUR: SRAM X5, 10-speed, long cage
CASSETTE: Sunrace, 10-speed, 11-36
RIMS: RH Disc 29", alloy double-wall, 26mm, pin joint, 32h
FRONT HUB: Specialized disc, alloy, Hi Lo flange, RCC ball bearing system, steel axle, QR, 32h
REAR HUB: Specialized disc, alloy, Hi Lo flange, RCC ball bearing system, steel axle, steel cassette body, QR, 32h
SPOKES: Stainless, 14g (2.0mm)
TIRES: Specialized Ground Control Sport, 29x2.1", wire bead, 60TPIView attachment 2

 

[RoadWrinkle]

...

 

[footloose]

Main difference between the two is A1 aluminum frame on the Rockhopper and M4 Aluminum alloy on the crosstrail. These are Specialized marketing names, but I have read the M4 is lighter and stronger. Also, both bikes have the same frame geometry in terms of dimensions, but the Crosstrail's design has a larger triangle.

Both look like great bikes. And are more or less identical as far as geometry. I'd be happy to find either under the Christmas tree.

So, given above and what you are designing to achieve... if the Crosstrail is
a) possibly lighter,
b) possibly stronger,
c) has even slightly larger triangle space...

Sounds like Crosstrail is the winner.

 

[majornelson]

Both look great. Although I love my hydraulic disc brakes on my a Trek, I had to shim the rear to fit and I couldn't use ebrakes- which means no PAS or cruise control for me.

I really like cellmans packs, have you checked the dimensions of his smaller triangle bag vs. the frames you're considering?

 

[Kent]

Crosstrail: FORK: SR Suntour NCXi Coil, magnesium lower, custom integrated fork crown, hydraulic lockout, 50mm travel

That is very little travel-this will ride like it has hardly any suspension at all. Good frames though.

Also, why 29" wheels? Many here seem to favor going to smaller wheels to improve performance and reduce stress on the motors.

 

[100volts+]

I like specialized bikes but I don't like hydraulic brakes. I like mechanical disc for ease of use.

 

[Ykick]

The Crosstrail appears to have a larger (46-48T?) chainring which is indicative of more street than trail orientation. It also looks slightly, maybe a bit larger triangle? 50mm travel fork isn't much but for street that's probably acceptable.

I too wonder about the 29" wheels? I could get along with that for the front wheel and I suppose with disc brake you'd have less obvious but wider range of choices for the rear? Biggest drawback of 29" in my limited opinion is with tire choices and motor RPM? But, maybe run the 29" front and substitute fat 20-26" for the rear? Fatter rear tire the better for hard tail IMO….

Either one of those would require a steering stem riser for me but that's par for pedal bikes.

I like hydro brakes. I wouldn't pay dearly for them but 'already own the tools and experience to maintain I give them a slight edge in feel. Obviously a subjective thing.

 

[majornelson]

+1 to 100volts+. The mechanical brakes offer more flexibility. Easy to lengthen or shorten the cables and move or replace the levers.

My trek is a 29er. 29 and 700cc are basically the same. I'm running a Mac 8t 700cc rim but would most likely go with a 10t second time around...

My recommendation to help smooth things out and protect against flats are schwalbe big apples. I swapped out my hybrid tires for these and they're great for street and gravel trails, fire rods, etc. incredible cushion without giving up the grip.

Just to clarify, a 29er is 622mm ISO for a wider 700c tire (Sheldon Brown). But my 29er big apples fit the 700c rim from cellman.

 

[melodious]

I've only been to Hawaii once and that was as a nightly stopover to Asia so I really never saw it's beauty . You'd figure that it would get attention from Asian products (Hawaii has the largest % of Asian races in the USA) since it's relatively close and would be a good stopover for shipping

As far as bikes go, I'd make my decision based on these criteria: 1. the amount of width allowed for large aka fat tires on the rear 2. the dropout design (not a big fan of these two for this reason) 3. amount of triangle space

I'd go with the Rockhopper.

Are you midmounting or going with a wheel motor? :wink: I'd think this would be an ideal bike for midmount.

 

[Drunkskunk]

The rockhopper is a better bike all around, but yeah, it does have a smaller triangle. However, the frame spacing will be better for the larger tires.

Take that corporate propaganda on the crosstrail's frame being lighter and stronger with a grain of salt. They are going to put the stronger frame on the bike that gets more abuse, the off road bike. Any mention of the road bike's frame material being stronger doesn't mean the frame it's self becomes stronger. It just means they could use less of it to make a frame that would be strong enough for the road.

But there's a problem with both bikes. If you're going for a rear motor, your SOL with the drive line on either of those bikes. No good way to make a conventional hub motor work with a 10 speed rear.

 

[RoadWrinkle]

Thanks to all for the input, as usual Es'ers come up with stuff I never even thought about. Good advice all around.

 

[Lebowski]

the read drop outs seem to be pretty different, maybe have a look how dificult / easy it will be to install some good torque arms ?

 

[dogman dan]

Both suck, for the reason stated above.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=50084

Lots of great frames out there in 26". Likely less choices in 29" Any bike can be converted to 7 speed rear, but it can cost you unless you have a bike junkyard like I do.

Lastly, if I was a thief I'd have that lock off either of those beautiful bikes in 1 second.

 

[RoadWrinkle]

Both suck, for the reason stated above.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=50084

Lots of great frames out there in 26". Likely less choices in 29" Any bike can be converted to 7 speed rear, but it can cost you unless you have a bike junkyard like I do.

Lastly, if I was a thief I'd have that lock off either of those beautiful bikes in 1 second.

Yes, I found it hard to find a new hardtail with flat dropouts, but think I can buy or fabricate custom TA's for the disc mount's on one side and then a GRIN universal on the other side. I have also seen derailleur bracket-TA combo's that I may try to find for the non-disc side of the hub. The point being that overall fit, comfort and performance of the bike was my primary criteria. I am thinking there are many work-arounds to install good TA's. As far as the pretty bike theft issues, cannot help that. I sold off my vintage amp collection to get into this hobby, so I have a little budget and decent used bikes are extremely hard to find on Maui (saltwater...). Anyway, I was also planning to put a new 7-speed cassette on whichever bike I buy. The shop I am going to buy at will do it for free after I by the parts from them... they also will swap out some riser bars for me as well. Just need to make a decision.

The main issue I have is the triangle size on either bike. I know I can configure more than enough LIPO to fit in there, but I am more comfortable with LiFePO4. Anyone know where to get a good 48v 10-15Ah LiFePO4 BOTTLE BATTERY?

 

[dogman dan]

No, the bottles are generally made with limn, because it's much smaller in physical size per ah.

Grin's universal TA should work fine for lower power builds, say 2000w or less. Above that, then you need to look for the beefy strong rear dropout area.

I understand that the bike market in Hawaii is not easy like it is for us on the mainland. But seriously, since you have to get it shipped in anyway with a new bike, other than price, why not a surly?

 

[torker]

All of the bottle batteries I have seen are still too long to fit in the triangle, at least in my Rincon. Unless you get the little 8 ah bottles. Not enough. Might have to check out the triangle batteries by Cellman.

 

[RoadWrinkle]

No, the bottles are generally made with limn, because it's much smaller in physical size per ah.

Grin's universal TA should work fine for lower power builds, say 2000w or less. Above that, then you need to look for the beefy strong rear dropout area.

I understand that the bike market in Hawaii is not easy like it is for us on the mainland. But seriously, since you have to get it shipped in anyway with a new bike, other than price, why not a surly?

Well, shipping is what I want to avoid for two reasons: about $350 to get anything here, but more important, these two bikes are here now, so I had a chance to test ride both. I also test rode other brands on island as well, again because they were physically here. I am shying away from ordering anything and having it shipped because it may not feel right once I get on it. That is the main reason I am doing a DIY build as opposed to just buying another pre-built like I did with my Motiv eCruiser (which feels great for what it is). I want to verify fit and comfort, find the right bike first, then choose e-components accordingly. I was honestly surprised how different all the brands I tried were so I am glad I took the time and found something I like.

BTW: I bought the Rockhopper Comp. and I am now considering going with the new Bafang 750w 25 amp crank drive kits so I do not have to deal with cassettes (can keep my ten speeds), can use the cool new wheels the bike came with,no dropout issues, no TA's etc. The kits are available with a nice 48v 11Ah battery that would fit on the down tube perfectly.... $1600 delivered to Hawaii for the kit, motor and battery...my PayPal finger is heating up... 8)

 

[mailmanx]

BTW: I bought the Rockhopper Comp. and I am now considering going with the new Bafang 750w 25 amp crank drive kits so I do not have to deal with cassettes (can keep my ten speeds), can use the cool new wheels the bike came with,no dropout issues, no TA's etc. The kits are available with a nice 48v 11Ah battery that would fit on the down tube perfectly.... $1600 delivered to Hawaii for the kit, motor and battery...my PayPal finger is heating up... 8)

Do you have a link to that kit?

 

[RoadWrinkle]

Mailmanx: Sure, fellow ES'er "lcrewse" (LeGrand Crewse
http://www.lectriccycles.com).

 

[dogman dan]

Crank drive does eliminate all the issues I mentioned about the dropouts.

It also eliminates any issues with the large wheels.

 

[RoadWrinkle]

Crank drive does eliminate all the issues I mentioned about the dropouts.

It also eliminates any issues with the large wheels.

Ya, the only hesitation I have is the 73mm bottom bracket on the Specialized where the crank drive is for 68mm, so I would have to use 5mm spacer and move the chain line, wondering if it would be prone to derailing the chain...I guess I should start that discussion under the non-hub builds section...oh wait I already did.