Short cranks but not square taper?

othello

I'm drawing a blank trying to find some short (155mm) cranks that don't run on a square taper BB, and wondered if anyone had ever come across any?

Both my son and daughter run short cranks on their road, track and MTBs -- I've built all these bikes myself and always specify short cranks. However they all run on square taper BBs, which are pretty heavy.

So I'm on the look out for a short crankset with external bearings, as they will be much lighter. I've seen a couple of BMX cranks (e.g. Redline micro 2) in the right size, and they are 110BCD, but I don't think they can take 2 chainrings.

Any suggestions?

keezx

1-Ignore 100-150 grams and keep on using square taper.
2-Have shortened Al cranks (not hollow) by cutting and tapping new pedal holes.
A lot of fuzz and no noticable gain....

simon_masterson

Get good square tapers then. The benefits hugely outweigh the small weight penalty.

cycleclinic

Ta specialities cranks are not heavy and with a light bb you will have something as light as 105 chainset and bb but costing more. It will be short though.

dj58

Middleburn make 160mm double ring cranks if you can't source 155mm, their R02 X type 110BCD cranks are compatible with HT II external BB's. You can buy light square taper BB's if you are prepared to spend money.

othello

Thanks all. I was seduced by the perceived lightness etc of non square taper!

A good point about going for decent square taper bottom brackets. I have a lot invested in these short cranks (6 bikes in total). They are all running a standard Shimano UN55 cartridge, which weighs a ton. Any suggestions for lightweight square taper ones? JIS taper , and both road bikes are running 10 speed Shimano, on standard 68mm bb shells.

keezx

A BB UN 55 is about 300 grams.
A really light BB will be about 200 grams.
Nobody will really be hold back by 100 grams , just a sip of water.
Maybe it's cleverer to look at all other parts and there might be a better place to save weight.
A simple saddle+post switch might do the same....

Don't know the weight of Token but suppose it's around 200Gr.
http://www.planetx.co.uk/i/q/BBTKJISCBN/token-jis-square-taper-sealed-carbon-body-bottom-bracket

Edit: the Token is 205 gr. (steel axle)

imposter2.0

As others have said - I really wouldn't worry about the weight issue (or non-issue). Youth racing is 99% flat circuits anyway (apart from Blackpool or Hog Hill), where weight is almost totally irrelevant.

Grill

If your kids aren't fast with 150g penalty, then they'll never be fast. Stick with what you've got until they're sponsored and then let them sort it out.

othello

Thanks all, really interesting feedback.

I'm trying not to be a total weight weenie, and my two are fast enough as it is.

But I thought if there was a sensible reason to upgrade away from square taper then I should. But the weight difference is negligible, and what is more important is them learning to spin with short cranks at this age.

maddog 2

Rotor go down to 160mm, I think, and will run on external bearings. The missus has some.

Matthewfalle

I had square taper and an old 105 crank on the summer fast commuter/trainer.

Wanting to save weight, I popped on a FSA Gossamer crank and matching fancy Dan external b/b - I got a deal on them so only cost me £50.

Total weight saving: 22grammes or something silly.

Keep the square taper, get some lighter pedals. Or handlebars, or tires.