RTIII
1 kW
Chalo said:
Darn, I'm stuck for the moment with only 7 gears in the cassette...
Help with gearing issues on E-Bike conversion
- Thread starter RTIII
- Start date
Darn, I'm stuck for the moment with only 7 gears in the cassette...
Chalo
100 TW
RTIII said:
Cassette? Or freewheel? They're not the same, and not compatible with the same wheels.
RTIII
1 kW
Chalo said:
Yes, thanks, I'm all too painfully aware of the distinction between freewheel and freehub!
I'm right now waiting on spokes of the right length so I can complete my wheel building of a new wheel for my 27" wheeled bike - with a free hub. The bike was fine as-was, but when adding the TSDZ2, I instantly realized I had a gearing problem because of the owner reported cadence level cut-out of the unit. ... While VERY recent rumor has it that this has recently changed - and my unit is as new as they come - it appears this mid-drive stops assisting at any pedal-RPM over 90. And, so, when I did the math, I realized this would prevent me from achieving the speeds I want / expect / need. So, having learned bicycle wheel building as a teenager (by necessity - and, while no expert by any means, I was reasonably OK at it), I boldly bought a new wheel (designed for a freewheel), complete, and figured the spokes would work out, just swapping to my new Shimano "Nexave FH-T300 Silent Clutch 130mm 36H 7-Speed" rear axle. To my chagrin, it turned out that the spokes that came with are a tiny bit too long. When relaced, ALL the spokes bottom out in the nipples just before they become taught enough to consider safe. As you increase the tautness and attempt to true the wheel, it quickly becomes clear there's no adjustment room to do so. So, I have some on order... I went 2mm short, and probably should have ordered 1mm longer than I did, but... they should work. -shrug-
Because my bike has to serve several functions and I don't want multiple bikes, I am now investigating a change in tires (if not wheels) to something wider that can take a heavier load on our crappy streets here in Oakland while still being efficient. If I can do it on the same wheel, great, or if I can change wheels, OK, and if I have to, I'll consider, budget permitting, a frame that's a bit more modern. In the mean time, I'll be using a 7 gear Shimano CS-HG41-7 11-28T “Road & Mountain bike” Hyperglide gearset in the rear.
I'm one of those "bewildered" by all the past stupidity in the bike world's nomenclature of rim & tire size and one thing I find intriguing is how I just measured the ERD (effective rim diameter - basically the end of where the spokes belong) of my new "27 inch" rim and found it to be 621mm and I also find that that's so damned close to the 622 measure of a "700C" wheel! I measured from there and the additional sidewalls of the rim are 5mm, adding 10mm to the whole diameter, and therefore about 632. But that's NOT how the rims are measured, as I understand it, rather, they go to the bottom edge of the sidewall where the tire bead should seat, and there, the number is right about 623 - within one mm of a 700C! Yet, some say the "27 inch" is actually 630 in diameter, so... Hmmm...
(Any insights on this greatly appreciated!)
Anyway, thanks for your remarks - the community here is very warm and helpful, and I appreciate your contributions.
Chalo
100 TW
Ah, I see your issue with the 7-speed freehub. There are plenty of cassettes for them, but not a great variety of sizes, and new 7-speed cassette hubs aren't being made anymore as far as I can tell. (Sort of like 27 inch wheels, but not as far down the road of obsolescence.)
Sheldon Brown used to suggest a modification he called "8 of 9 on 7". It's a pretty ingenious way to update a bike whose rear spacing doesn't allow easy use of 8/9/10 speed cassette wheels. You simply take a 9-speed cassette, remove any single sprocket and spacer except for the outermost small one, and mount the remaining 8 sprockets on a 7-speed freehub. Then you use a 9-speed chain, shifter, and derailleur (or as Sheldon would have put it, "derailer"), setting the limits to lock out the non-existent innermost gear.
While it costs significantly more to do this than to use 7-speed parts, it would allow you to take advantage of the much greater variety of currently available cassette sizes for 9 speed systems. If that's what you want.
The ISO diameter of a rim isn't easy to measure. It's the diameter of the bead seat-- the location where the tire bead is supposed to locate in the rim sidewall. The ERD is always smaller, and the rim outside diameter is always larger than the bead seat diameter.
Sheldon Brown used to suggest a modification he called "8 of 9 on 7". It's a pretty ingenious way to update a bike whose rear spacing doesn't allow easy use of 8/9/10 speed cassette wheels. You simply take a 9-speed cassette, remove any single sprocket and spacer except for the outermost small one, and mount the remaining 8 sprockets on a 7-speed freehub. Then you use a 9-speed chain, shifter, and derailleur (or as Sheldon would have put it, "derailer"), setting the limits to lock out the non-existent innermost gear.
While it costs significantly more to do this than to use 7-speed parts, it would allow you to take advantage of the much greater variety of currently available cassette sizes for 9 speed systems. If that's what you want.
The ISO diameter of a rim isn't easy to measure. It's the diameter of the bead seat-- the location where the tire bead is supposed to locate in the rim sidewall. The ERD is always smaller, and the rim outside diameter is always larger than the bead seat diameter.
RTIII
1 kW
Chalo said:
Doah! ... Still see PLENTY of new ones on e-bay, for example...
Chalo said:
...Believe it or not, I speculated about this myself when I learned that on my own new cassette the outermost gear was floating free. It got me thinking about those wider cassettes. I am to understand that the spline arrangement is the same on the vast majority of cassette systems, so... When I look at my 7 speed, there's a riveted on PLASTIC spacer set which just keeps the set of gears in alignment. It occurred to me that it'd be pretty easy to drill out the rivet and do whatever you wanted with regard to your gear stack. Of course, one glance may not tell the whole story but it's very suggestive to a creative person like me - who happens to have his own machine shop! 8)
Chalo said:
Again, helpful comment. I'm thinking I can use a pair of pointers like a giant caliper, one from below, fixed, another from below, dangling from a literal thread - easy to adjust! - directly above the lower one. Index by hanging the upper one first like a plumb bob, then positioning the lower one to dead center underneath it. Then draw the upper one up to a little more than wheel diameter, set the rim on the lower one in position and then lower the upper pointer until it's in the right spot and anchor it. Remove wheel, measure gap... Not too hard. I have a two meter measure in mm.
But, does one really need to bother - other than finding the right spokes? I'd think this is all well known today! (Or, maybe not!) All I want to do is find if I can replace the wheel with something wherein I can have more modern features - like a freehub instead of a freewheel!
I'm still in the period where I could possibly return the freewheel based wheel. And I'm thinking that if I'm going to return it I should do it now! So, I've gotta make a decision soon. (And there's brake reach to consider!)
If you mean "well known" as in once you measure a wheel of one rim size you can use that to fit another for spokes, then no. Each rim model could have a very different ERD depending on how it's cross-section is shaped; where the nipple holes end up.RTIII said:But, does one really need to bother - other than finding the right spokes? I'd think this is all well known today! (Or, maybe not!) All I want to do is find if I can replace the wheel with something wherein I can have more modern features - like a freehub instead of a freewheel!
If you mean "well known" as in how to measure this stuff, then sure--and the manufacturers know how to do it too, and should print it on the rim or list it on their website for bare rims. But for a built wheel, there's no big reason to bother, cuz you don't "need" to know--the wheel is built and spokes are already in it of presumably the right length. Theoretically if you needed more spokes for that wheel then you could just measure an existing one.
It's a problem when doing things like taking an existing wheel apart and reusing the parts for other wheels, though--but that isn't really their problem, just ours.
If you mean "well known" as in measuring one wheel and comparing it to other whole wheels for replacing in a specific frame's limitations, then...mostly. It still depends on what rim they used, because they might use a taller rim edge than expected, making it a lot harder to get a specific tire onto it that worked fine on another wheel of the "same size", or they might use a shorter rim edge than expected, making the same tire so loose that airing it up could pop it off the edge of the rim (though this usually only happens when the rim isn't really the right width for the tire anyway).
In theory there's numbers available from the manufacturers of all these things (maybe even printed on the items) that allow us to figure out what combinations will work and what won't. But for the most part, people don't even know that this matters, much less what all those numbers mean or how to use them to find out.
I don't have much experience with the numbers, cuz they're not usually on the parts when I get them used, and/or I don't have a lot of choices and have to just make them work together until I find a better solution. So I'm not the person to give detailed math answers about it all...but I do know there *is* a way to find out short of experimentation.
RTIII
1 kW
amberwolf said:
Yes, that's what I meant.
...Do I have any choice in tire width on my 27" X 1 1/4" rim? I'm running Kenda K35 27” x 1.25” / 32 - 630 right now...
If there are no wider options, I'm thinking of MAYBE trying a 700 wheel - not sure what that'll do to my brakes, though. If I understand right, I'll need "long reach" calipers...
Chalo
100 TW
RTIII said:
27 x 1-1/4" is the most common size by far for 27" wheels, but there are a few 27 x 1-3/8" tires still around. And there's the Michelin World Tour, which is labeled 1-1/4", but is larger than some tires labeled 1-3/8".
If you have enough adjustment left to slide your brake pads down 4mm in the slots, you can use the same brakes for 700c. Otherwise, yes you will need calipers with longer reach.
Most 27" bikes will accept 700x40 tires with some operating clearance.
RTIII
1 kW
Chalo said:
Thanks, Chalo,
More excellent data to consider.
I spent some time this AM looking through available wheels in 700C. My frame was 122mm and I opened it up to 130 last night. So, this is a bit of a limiting factor - not sure I want to do 135... But then, maybe I should. I'm unsure.
Since this thread is focused on gearing issues; I am not delighted to reduce the diameter of my wheel / tire any! ...What's a realistic diameter, to the outside of the tire, of something like a 700C with a 30mm or 35mm sized tire? If I have some numbers to chew on, I can plug them into my spreadsheet. Let's recall our TSDZ2 units have a pedal-RPM limit of about 90, so this matters...
An unrelated question: I hear I should get modern brake shoes; any advice about that?
Thanks Chalo - BTW, what's with the cat-hat?! Is that a real cat on your head?!
Chalo
100 TW
RTIII said:
You can further widen the frame, or you can reduce the spacing of a 135mm hub to 130mm (and correct the dish by tightening the right side spokes), or you can just spring the frame open to fit a 135mm wheel every time you install it. Of the three, I'd widen the frame if I were working with a traditional lugged steel bike like yours.
The height a tire sits above the rim varies from tire to tire, even in the same width, and it varies according to the inside width of the rim, too. (Tires sit taller on a narrower rim.) It's not possible to generalize, except that wider tires are usually taller than narrower ones. Expect the tire to stand an amount equal to its width above the bead seat and you won't be wildly wrong. I just measured several inflated tires around my place and got measurements higher, lower, and equal to that amount.
700x38 will almost always be larger in outside diameter than 27x1-1/4". The one possible exception would be a short 700x38 versus a Michelin World Tour.
Brake pads are made of rubber, and they harden with age. OEM pads particularly do not perform well when they're old. Get Kool Stop Continental or Supra pads with Salmon compound and you won't be sorry. It will surprise you hope much your brakes can improve.
Thanks Chalo - BTW, what's with the cat-hat?! Is that a real cat on your head?!
That picture is about 12 or 13 years old now, and yes, that's a real cat named Oscar. He was particularly lazy and inert, even by cat standards. Grooming himself was the only thing he had any enthusiasm for.
markz
100 TW
Yeah Kool Stops are the way to go.
Couldnt find any on Chain Reaction Cycle website.
But I did find these
Clarks 72mm Anti-Lock Anodised V Brake Pads
http://www.chainreactioncycles.com/ca/en/clarks-72mm-anti-lock-anodised-v-brake-pads/rp-prod89743
Wondering what opinions you guys have.
Cheap as Borscht
Couldnt find any on Chain Reaction Cycle website.
But I did find these
Clarks 72mm Anti-Lock Anodised V Brake Pads
http://www.chainreactioncycles.com/ca/en/clarks-72mm-anti-lock-anodised-v-brake-pads/rp-prod89743
Wondering what opinions you guys have.
Cheap as Borscht
RTIII
1 kW
markz said:
They're certainly cheaper than what I paid. I paid $40.50 for four Kool Stops, inserts and holders (and related washers and nuts), including shipping.
One thing about the Kool Stops that surprised me is that the holders have a ball end and can be articulated off of the perpendicular to the plane of the wheel. This would be great to accommodate rims that bevel inward or outward or what have you. ... Maybe this is normal for modern units, I don't know, most of my experience is from decades ago!
Chalo
100 TW
RTIII said:
That's typical of brake pads for linear pull brakes, because the brakes lack any means of angling the pads like cantilevers, and can't easily be bent for toe-in like calipers. Today's road brake pads usually have a shallow spherical washer and a curved surface on the pad body to accomplish a rudimentary version of the same thing.
One of the most common signs of a bike having been serviced at home, is the stack of spherical adjusting washers assembled all wrong so they can't gimbal. They seem self-evident to me, but not to everybody.
markz
100 TW
Chalo said:
Chain Reaction Cycle has BLACK or Salmon color, Salmon color is sold out.
Is there a compound difference between the colors?
http://www.chainreactioncycles.com/ca/en/kool-stop-supra-2-brake-pads/rp-prod46439
Chalo
100 TW
markz said:
Yes, there is a difference. They work somewhat similarly in dry conditions, but Salmon is much stronger in the wet, lasts a lot longer, and is less abrasive to your rims. It's also a little more likely to squeal, if your brakes are prone to that.
I have heard trustworthy endorsements of the gray E-bike compound pads as being even significantly better than Salmon.
markz
100 TW
TYVM Chalo
Kool Stop has so many SKU's
Kool Stop ebike T3 Supra 2 e-bike and 3 others
I had these ones from MEC, waste of money.
Kool Stop has so many SKU's
Kool Stop ebike T3 Supra 2 e-bike and 3 others
I had these ones from MEC, waste of money.
RTIII
1 kW
I ordered a new front derailleur that's supposed to mount with a "braze on" ring since the fact that the derailleur doesn't have a built-in bracket to attach it to the seat tube means that maybe I can fabricate a mounting that would move it outboard to accommodate the TSDZ2's distance from centerline. This would let me have two working chainrings - maybe three!
However, along the way, I went to a local bike shop where a technician named Calvin suggested just bending the existing unit.
So, when it came time to do the work, I checked it out and indeed, tweaking the existing derailleur worked fine! 8) So, now we're back to two front chainrings, a 42T and 52T! :lol:
My only problem with the setup now is that the 11T jumps when torque is applied. I'm going to try installing a new chain today and see what happens!
However, along the way, I went to a local bike shop where a technician named Calvin suggested just bending the existing unit.
So, when it came time to do the work, I checked it out and indeed, tweaking the existing derailleur worked fine! 8) So, now we're back to two front chainrings, a 42T and 52T! :lol:
My only problem with the setup now is that the 11T jumps when torque is applied. I'm going to try installing a new chain today and see what happens!
RTIII
1 kW
So, just tried a new Shimano chain on my TSDZ2 powered 1982 Raleigh replica...
Just as a refresher on where it's at now, it's now sporting a new Nexave FH-T300 Silent Clutch 130mm 36H 7-Speed freehub laced into a new Sta-Tru 27" X 1.25" wheel with new Shimano Hyperglide CS-HG41-7 11-28T cassette, and the original TSDZ2-supplied steel 42T, and some random 52T steel chainrings... Still running both original 1982 Shimano derailleurs, and get all gears perfectly - EXCEPT the 11T was hopping / skipping under torque.
Today I just installed a new Shimano CH-HG71 6/7/8 chain and it works perfectly! IT CURED THE 11T FROM HOPPING! 8) :lol:
I am so delighted!
MY THEORY, supported by the math, is that with the formerly highest gear, a 13T, my cadence speed at 25 MPH was right at the upper limit of the TSDZ2, which is why I had trouble piercing beyond that speed. However, now with the 11T in action, I should be able to get it up to about 29 MPH before reaching that same cadence limit.
Hmmm... If I can get to 29 MPH, I'll be debating with myself if I want to try a 54T! :lol: :lol:
Just as a refresher on where it's at now, it's now sporting a new Nexave FH-T300 Silent Clutch 130mm 36H 7-Speed freehub laced into a new Sta-Tru 27" X 1.25" wheel with new Shimano Hyperglide CS-HG41-7 11-28T cassette, and the original TSDZ2-supplied steel 42T, and some random 52T steel chainrings... Still running both original 1982 Shimano derailleurs, and get all gears perfectly - EXCEPT the 11T was hopping / skipping under torque.
Today I just installed a new Shimano CH-HG71 6/7/8 chain and it works perfectly! IT CURED THE 11T FROM HOPPING! 8)
:lol: I am so delighted!
MY THEORY, supported by the math, is that with the formerly highest gear, a 13T, my cadence speed at 25 MPH was right at the upper limit of the TSDZ2, which is why I had trouble piercing beyond that speed. However, now with the 11T in action, I should be able to get it up to about 29 MPH before reaching that same cadence limit.
Hmmm... If I can get to 29 MPH, I'll be debating with myself if I want to try a 54T! :lol: :lol:
RTIII
1 kW
I made a small oops here:
The 13T reference was correct, the 11T was not - read the wrong line off the chart! IN THEORY, I'd be doing 34.2 MPH at a cadence of 90 PRPM!
Ooo Baby! 8)
Somehow I think I'm not ever going to get there, but at least I'm unlikely (except maybe on a long downhill) to get it over the motor RPM of the TSDZ2!
RTIII said:
The 13T reference was correct, the 11T was not - read the wrong line off the chart! IN THEORY, I'd be doing 34.2 MPH at a cadence of 90 PRPM!
Ooo Baby! 8) Somehow I think I'm not ever going to get there, but at least I'm unlikely (except maybe on a long downhill) to get it over the motor RPM of the TSDZ2!
markz
100 TW
http://www.road-bike.co.uk/articles/cyclingcadence.php
I got a few 52T chain rings I may use. I saw a 11 speed with 52T cassette on it but thats climbing hills (small front, large rear)
I think the lowest tooth count rear is 11T and perhaps 10T is available, perhaps.
https://www.pinkbike.com/news/Ten-Speed-and-the-Nine-Tooth-Cassette-Cog.html
Here is a 10-42 cassette, not a freewheel - Very expensive.
http://www.bikeman.com/FW6112.html
https://sheldonbrown.com/capreo.html
I got a few 52T chain rings I may use. I saw a 11 speed with 52T cassette on it but thats climbing hills (small front, large rear)
I think the lowest tooth count rear is 11T and perhaps 10T is available, perhaps.
https://www.pinkbike.com/news/Ten-Speed-and-the-Nine-Tooth-Cassette-Cog.html
^^I dunno if this is even a product, the last web page I found was from 4 years ago.
Here is a 10-42 cassette, not a freewheel - Very expensive.
http://www.bikeman.com/FW6112.html
https://sheldonbrown.com/capreo.html
Chalo
100 TW
Every reduction in sprocket size below 16 teeth makes a measurable, palpable reduction in efficiency and increase in wear, with each successive step down having a larger negative effect than the previous one. 11t only works passably well because pedal cyclists don't resort to using it very often.
It's a much better approach-- more durable, more efficient, and smoother-- to use larger front sprockets to achieve higher gear ratios. This is especially true for e-bikes, where the highest gears are used more often than on pedal bikes.
It's a much better approach-- more durable, more efficient, and smoother-- to use larger front sprockets to achieve higher gear ratios. This is especially true for e-bikes, where the highest gears are used more often than on pedal bikes.
markz
100 TW
Then too you have to look at plausible "capacity" of the gears and derailleurs. I find with my bike I use the middle front crank all the time because I dont have it hooked up, just set-locked. Same with the rear. Its a motor only ebike, with a helping hand.
RTIII
1 kW
Chalo said:
Yes, and that's exactly why I intentionally designed (and fabricated) my dual chainring adapter to be able to accommodate THREE chainrings up front ... and if I ever get the idea that I've reached the max assist pedal RPM of the TSDZ2 but that I should be able to go faster, I might just get a taller than 52T chainring up there! :lol:
...I think people aren't aware just how reduced the contact area is with such small gears.
The 13T, my next gear down, does pretty damned well all on its own but I definitely got the perception that I had reached the max assist speed of the TSDZ2.
James Broadhurst
100 W
I, stupidly, thought there would be no problem with the chain line and the 42/52t chain rings are on their way. Being pessimistic, the chain's about a full chain width (8-10mm) out. I need to move the front derailleur out by that amount. Is this tweaking or needing something an awful lot more persuasive e.g. Lump hammer?RTIII said:
Chalo
100 TW
The screws on top of your front derailleur are limit screws, used to set the extremes of the derailleur's travel. By tightening up the inner limit and loosening the outer limit, and readjusting the cable accordingly, you can relocate the derailleur's travel outward.
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