Fitting a 52 teeth crank to my Saracen

[widowmaker]

I am in the pursuit of the impossible, the one bike fits all my uses

I think I may have almost built it

My Saracen Traverse which was kindly karma'd to me on here has done some solid roadwork with the fitting of some Schwalbe City Jets, it was far more comfortable than my old road bike - no pain in the back/neck and able to cope with the slightly rough roads where I live - but after taking part in a 38 mile Charity bike ride yesterday I noticed that my top gear is lacking a little compared to my roadie friend as am using too much energy keeping up on the flats/downhills.

I know that it will never be a proper road bike, but wondered if its possible to swap my one piece crank for one with a larger crank, I think mine is 42T and wanted something nearer to 52T

Is it possible ?

Would I need a longer chain ?

I assume the front derailleur would need to be raised ?

 

[hamster]

You will need a longer chain, and also need ot consider the effect on the inner ring - the front mech may not reach far enough down.

Provided you have something like a 110" gear there is really not much extra you need - that's about the same as 52/13 on a road bike, or 44/11 depending on the tyre size you are running. Are you spinning out on the flats? If not then more likely the problem is that you have more drag and a less aero position than your roady pals - but that's why you opted for a more comfortable bike...

 

[widowmaker]

You will need a longer chain, and also need ot consider the effect on the inner ring - the front mech may not reach far enough down.

Provided you have something like a 110" gear there is really not much extra you need - that's about the same as 52/13 on a road bike, or 44/11 depending on the tyre size you are running. Are you spinning out on the flats? If not then more likely the problem is that you have more drag and a less aero position than your roady pals - but that's why you opted for a more comfortable bike...

I am spinning out on the flats not massively but when they kick, I struggle to keep up but downhill they are much much quicker than me.

I am running 26" wheels with 1.5 City jets.

I just want to get the maximum possible out of this bike

 

[FluffyChicken]

Re:

No idea what crank you have now but you can go for 48 (which I use) 50 and 52 rings top ring on an MTB triple.

The 48 works fine with 24T granny gears with a 28-11T cassette.
And a normal front mech m900/901 in my case with an m900 rear mech.

Of course you'll need a longer chain

 

[widowmaker]

Re: Re:

No idea what crank you have now but you can go for 48 (which I use) 50 and 52 rings top ring on an MTB triple.

The 48 works fine with 24T granny gears with a 28-11T cassette.
And a normal front mech m900/901 in my case with an m900 rear mech.

Of course you'll need a longer chain

I have a standard shimano one piece crank with a 42T, which I was planning on replacing anyway with a STX RC one I have.

A 48T would do the trick, at least allow me to hold my own and carry the 'Retro' flag

 

[legrandefromage]

I built something like this by using a road chainset, a long chain and a chain tensioner. This gave me all the ratios without stretching anything beyond its capaicity.

I have spare 50t 110 BCD chainring for postage if you want it.

 

[hamster]

You will certainly get away with a 24T difference on the front before the mech scrapes on the bottom of the cage and probably 2 more.

 

[widowmaker]

I built something like this by using a road chainset, a long chain and a chain tensioner. This gave me all the ratios without stretching anything beyond its capaicity.

I have spare 50t 110 BCD chainring for postage if you want it.

Thanks for the offer, I shall check the BCD of the STX RC crank I have.

 

[legrandefromage]

ah, thats 94. cant help there.

 

[FluffyChicken]

Re:

I'm not sure what a standard one piece crank is you talk off, Especially with shimano, I didn't know they made them for mtb.
I know bmx have them.

I assume some early 80s thing?


I know what an stx crank is though.