Olgaimage

Hello

I have been searching the net for hours to find a 160 mm crankset that fits my bike. Does anyone know a site or brand that sells 160 mm cranksets? I have looked on eBay and speedandcomfort.com, but the short cranksets there don't fit my bike.

phtomita

What bike, bb do you have?

Olgaimage

I'm sorry, I just realised that I don't need a new crankset but just the crankarms because I want them to be shorter. I thought that I had to get the entire thing changed. However, I don't know how hard it is to find 160 mm crankarms, so maybe I'll need help after all. But I am sorry and I would delete this thread now if I could.

fietsbob

J&B imports (wholesale to bike shops) has bike cranks start at 150 long .. usually for kids bikes ...


premium quality TA has 155, 165 .. https://www.peterwhitecycles.com/carmina-compact.php





...

Bluechip

Check with the recumbent forum. It's pretty common for short cranks over there.

Short Bicycle Cranks

alcjphil

Fine, but you still have not stated what crankset you have, or what sort of bike you have. There are all sorts of crankarms out there

jade408

Also, OP, they are not all interchangeable. So the more details on what you currently have the better!

mac_flyer9

Shimano 105 R7000 has a 160mm crankset available.

BlazingPedals

I find it hard to believe that a short crankset wouldn't 'fit' your bike. More likely, what you're finding is for a different bottom bracket style. To that I say, change the bottom bracket too. Replacing just the arms will bring on the same issues, and on top of that you may be swapping worn rings onto your new crank arms.

Rick

Schlumpf crank arms

Olgaimage

I don’t know what sort of bike I have. It looks like a racer bike as it is light and has narrow wheels but it wasn’t that expensive. The crankset has these features:
- 110 BCD
- 5-armed
- Tapered/square box
- 50/34T
- 8x2 speed

Olgaimage

Sorry, I know it doesn’t make sense now. I thought I had to have the exact same crankset as before with shorter arms.

What issues will will be brought on if I don’t change the bottom bracket?

Leisesturm

I have to ask why you think you need 160mm crank-arms? You do, in fact, need to have the exact same TYPE of crankset as before if it is to fit the bottom bracket spindle that is on the bike. Spindle/bearing sets are relatively cheap and as Blazing Pedals observes you could just buy the whole shebang and have no worries about what might or might not fit. But first ... why?

Olgaimage

Because I have 170 mm crank arms. I am 161 cm tall and have relatively short legs, so I don’t feel that there is much space when I pedal. I have a bad knee, and although it didn’t come from riding my bike, I hope to help it a bit by getting crank arms that fit me better

I feel a bit lost now, I don’t much about bikes and the guy from the shop made it sound like I just needed the arms (he saw my bike). I will call him again today

jgwilliams

Yes, you certainly could just replace the crank arms. You obviously have the information you need: 110bcd and square taper. Don't forget that when you fit shorter cranks you'll need to raise the saddle a little so that your leg is at the same stretch on the lowest part of the stroke. So if you're going from 170mm to 160mm that would be half that difference, or 5mm.

Leisesturm

I don't unerstand the bolded text above. 'Space'? 161 cm is about 5'2.5" more or less. No, not tall and possibly could benefit from shorter than standard cranks but I personally am Agnostic on crank length. More has to be considered than mere biomechanics. The cost of the new crank arms and the labor costs to swap over chainrings. I would not at all be surprised if the total went over $100. A lot over $100. I wouldn't do it. I know more than one female cyclist under 5' 2". One of them under 5'! They all have ridden for decades on standard cranks. It is a non-issue. Bad knees, knee pain. These are problems that IMO should be solved off the bike. The bike will neither make them worse nor make them better. Well... to qualify that ... being in too high a gear consistently can aggravate knee issues. Shortening a crank raises every gear on the bike incrementally. What if the answer to knee issues on a bike is actually longer cranks?! I don't think anyone knows for sure. So ... if I were you I would work with the cranks I have. I would also give this program a try.

Olgaimage

That actually looks good, I think. Does it fit a squared tapered box? Does it matter that it is for BMX bikes? Do I have to worry about the spindle type?

fietsbob

ISO (EU) and JIS (Asia) are different so know your BB , and there is ehe whole width and chainline can of worms ...


heavily discussed.. ... previously..





....

Olgaimage

Thank you for all your help!

If my BB doesn’t fit I can just replace it right?

Clyde1820

Thorn (@ SJS Cycles) makes a triple MTB crankset with various arm lengths.

From the SJS web site:
SJS Cycles also carries a number of JIS Square Taper bottom brackets: click.

* No affiliation.

BlazingPedals

Uh... no. If the crank arms are 10mm shorter, the pedal at the bottom of the stroke will be 10 mm closer to the bottom bracket and the saddle will need to be raised 10 mm. The Origin8 are reasonable quality, just a little heavy. I have a 155mm Thorn triple on one of my bikes. It is lighter and nicely finished. But it cost more, too.

Olgaimage

mtb_addict: I don't know if it is a 68 mm BB shell, I guess I'll have to talk to the bike shop again. I'll also ask them about how difficult it is to use the arms when they need a JIS BB. It really doesn't sound good that I maybe won't receive the left arm, I hope it's different on eBay but there are no reviews there.

Thank you for your input, BlazingPedals!

If the Origin8 crankset won't work, I have found 160 mm long Shimano FC-R7000 crank arms, but the matching crankset does not fit my cassette sprocket. However, the Shimano Claris FC-R2000 does, but you can’t buy it with 160 mm crank arms. Is it possible to use the Shimano FC-R7000 crank arms with the Shimano FC-R2000 chain rings? I feel that it is pretty safe to buy Shimano but much more expensive than just buying the Origin8 arms

jgwilliams

Yes you're absolutely right. I had my thinking backwards - the full stroke is twice the difference less or 20mm.

The other thing I was thinking about is that you may end up wanting to lower your gearing as you will probably adopt a higher cadence. So rather than just replacing the arms you might want to consider going for a compact chainset. Just a thought.

billyymc

https://speedandcomfort.com/collecti...y-short-cranks

Olgaimage

jgwilliams my chain set is 50/34T