jonwvara 

This is not my usual area--I'm a regular on the C&V forum--but I'm posting here because my wife and I are looking into buying an ebike for her. The Specialized Turbo Vado SL looks like a good fit in all the ways that matter, except one: As far as I have been able to find out, the SL models are only available with 165 or 170mm crankarms, and Vicky needs arms in the 150-155mm range, due to a limited range of motion in both knees. (Shorter arms are available for the motors used in the "full power" Specialized bikes, but neither of us are enthusiastic about heaving a 55-lb bike on and off of bike racks, etc.).

Does anyone here know of a source of shorter aftermarket crankarms for these bikes? I'm not even sure what the spline system is, since Specialized doesn't list it in their specs. I know that various bolt-on crank shorteners are available and would work, after a fashion, but they're kludgy and widen the tread by a good inch or more, which seems problematic to me.

Thanks for any help those with experience in this area have to offer.

cat0020

I've fitted 152mm crankarms onto my chain-less micro folding ebikes, since my wife is 4' 11" with shorter legs.
I bought the replacement shorter crankarms from AliExpress, with square taper b/b, they are much easier to source.
https://www.aliexpress.com/w/wholesa...atId=200003570

veganbikes

Unfortunately the above is of no help as a quick search would show the VADO SL is not using a hub drive or square taper. However they do exist you just need to find something for the SL 1.1 Motor which is what Specialized is using across their SL lineup (and Brose for everything else). I know Praxis does a set of carbon ones in 160 and I believe they are one of the main aftermarket suppliers of crank arms for the SL stuff. I bet though that White Industries might be interested as they do make custom crank arms for Bosch (our tech rep for Bosch has them on his demo motor and Schwift uses their stuff on some of their custom e-bikes) I would also look at Joseph Kuosac as Lennard Zinn uses his cranks and I know he does Bosch but may be interested in the Mahle motor as well. You might also reach out to Zinn and see if he has any leads as he deals with big and tall and short and small folks all the time so is well versed in different sized cranks. I also recall someone somewhere doing crank arm shortening but I cannot recall who?

The SL is a neat bike and your wife will likely love it.

jonwvara 

Good suggestions, thanks. Yes, Praxis does make a 160mm alloy crank for the SL 1.1 motor, but that's still too long. There's an outfit in Minneapolis called Bikesmith Design and Fabrication that does very professional work on crank shortening. Tapping in the new hole and leaving enough material below the new hole means that you need to start with a crank at least 22mm longer than the length you want to end up with--for example, to end up with a 152mm crank, you'd need to start with a 175. That's not an issue here, but most styles of cranks can't be shortened. If the crank necks down above the existing pedal boring, there won't be enough material on either side of a new hole for strength. Most newer cranks aren't styled this way, but unfortunately, most modern cranks (including the Praxis cranks) are hollowed on the back face, above the original pedal bore, to reduce weight. As a result there's not enough "meat" to tap into there.

I would have thought that aftermarket manufacturers would be quick to produce short cranks for popular ebikes , given that people with knee problems would seem to be candidates for going electric. I'll keep looking

As a former editor, it annoys me to no end that I mis-keyboarded the model of the bike in the title as "Vadio," rather than "Vado," and that Bike Forums doesn't let you edit thread titles. But it's my own damn fault, so I will have to grin and bear it.

Edit: attaching an image of the Praxis crank to illustrate the problem of the hollowed back side.

fooferdoggie 

there are few parts made for e bikes alone yet.

cat0020

I had 175mm Bontrager crankset (with Octalink spline) shorten (to 152mm) more than a decade ago on my wife's road bike.
Originally, I had fitted 165mm cranks, but her knees were coming up to high towards her chest on the upstrokes.
Workmanship was great, I don't remember how much it cost (more than a decade ago). but I remember I got the Brontrager crankset for cheap and had it done as an experiment.
I guess the experiment went great.

jonwvara 

Your photos look like the work of Mark Stonich, who was the originator or Bikesmith Design and Fabrication--I think (but am not sure) that he has since sold the company. Yes, they do nice work, and at reasonable prices. Vicky has a road bike with similarly shortened cranks, which have worked well for her. But ebikes are more problematic because there's not much interchangeability of arms.

veganbikes

I figured it is at least a good starting place. It is a tough one as I haven't seen much for the SL motor yet as I am always interested in upgrade parts. I will ask my contact at the Turbo department and see if there is anything they recommend. I am pretty sure Fazua (another lightweight system) has more options because I believe they are sharing the ISIS spline and offsets and such that Brose uses. If you can find an FSA crank they have stuff that is not hollowed out at the back and Hope does stuff down to 155mm in a bunch of fun colors as well but sadly no SL stuff yet but they mention it so maybe it is in the works (I Hope...lol)

I think Bikesmith is the one, that sounds really familiar.

Still good luck on it I wish I could wholly recommend the Fazua stuff but in truth I haven't had a chance to ride their stuff and especially their new motor which on paper is way better than SL but if limited to Euro spec speed at 18mph I couldn't deal with that one at least not for commuting and general road riding.

jonwvara 

Thanks again--you seem to have contacts in the industry, which is great. I'm a former bike mechanic, and a good one in my day, but as I said at the outset, I'm normally a denizen of C&V, so know next to nothing about e-bikes. For example, what is the actual spline pattern on the SL 1.1 motor, do you know? I don't think it's ISIS. Is it something completely proprietary? If I knew how to describe exactly what I'm looking for, I might have better luck finding it. .

veganbikes

Yeah I just emailed them so we shall see what they say, they are closed today because it is a New Year holiday. I am actually unsure of the specific spline pattern I want to say it is a ISIS spline as most everything else is and it looks like it could be close but I am guessing if so it is the offset that is the issue. Mahle the makers of the motor would probably know for certain but my guess is there is certain clearances and offsets they have to match as I don't know why they wouldn't use ISIS it is an open standard a lot of others are using to a lot of success. Hopefully my guy will come through with ideas if not I can ask a couple other folks and see someone has got to have options.

Luckily I do work in the industry still and handle a lot of warranty so I talk with a lot of folks all over and I am a bike nerd so I love the oddball sort of stuff. I love e-bikes for their utility and such but hate that the good stuff is hard to get as just a frame with motor and wiring it is all a complete bike for the most part aside from some MTB stuff (we built up a Levo SL for a co-worker which was a frameset which was cool but I want a Vado personally).

My Bosch bike came with FSA cranks (or likely FSA cranks re-branded) I had fitted some Rotor E-Kapic cranks which got swapped to RaceFace after the E-Kapics went Kaput (cracked the bolt and just were fiddly on my motor (looked good though) and so far all is good. The shorter cranks were helpful for me not so much for fit but more for pedal strike in corners but I only went to a 160 from 175.

tds101 

You're definitely an asset to the forum sir,... Happy New Year!!!

veganbikes

Thank you! and Happy New Year to all and an early Chinese New Year as well.

I love this place and wouldn't want to go to another forum. I have been on other forums in the past but this is the best : )

veganbikes

jonwvara No response yet but they were out of the office Monday and Tuesday so probably playing some bigger catchup from last year. However I am going to a Specialized training for the Electric stuff coming soon so if I don't hear anything I will ask there and see if they know or can get us an answer. I am really curious what I have missed if they exist and will be sad if they don't yet exist but maybe hearing that feedback will help push them since they do Retül to get Praxis and other on board.

jonwvara 

Thanks! I really appreciate your getting on the case and will be interested to hear what you find out.

veganbikes

Unfortunately nothing short enough but apparently it is using the Praxis Works M30 spindle so Praxis would be the company to ask and push for shorter cranks and it is possible someone somewhere makes an M30 compatible crank that isn't Praxis or maybe is and they have something shorter. If not maybe Joeseph Kuosac or maybe White Industries or Zinn might consider a custom project?

Good luck, I was hoping for better news but alas nobody has adopted it yet.

jonwvara 

Thanks for your efforts--I guess it will have to be the kludgy crank shorteners to start, and the hope that someone will eventually start making short crankarms. Or a least long crankarms with a non-hollowed back that can be shortened by a machine shop

veganbikes

You are welcome, glad I could help even if we aren't much further along!
I will ask one last time at the event I am going to but I heard from two different Spesh people but hopefully something will happen sooner.

veganbikes

I was at an event today and no luck but one of the other folks there from another shop did suggest 5Dev might be doing something SL at some point but it could have just been speculation. I tried to ask why M30 but nobody knew and we just made an ISIS joke. Hopefully someone soon will do something shorter.