njwbert

Hi, I would like to ask for help from people who have done conversions of road frames to fixed.

At a bike shop I frequent, the owner has this red steel salsa cycles frame with a 126mm rear horizontal drop out spacing. I was planning to get some IRO hubs and respace the hubs to fit the rear dropout. Now the only thing that I have a bit of problem (and inexperience) with is the BB spacing. It has a 73mm BB width (English thread I think, not much time lately to check). So what do I put there to achieve the "magic" chainline of 42mm with Sugino 75 track cranks?

Would the difference between a 73mm and 68mm BB width affect the chainline? Like a 68x113 seems to me like an effective 73x108. Of course I can only think of this when I am tired at night and back from work and my head is killing me...

I have questions but being in a country where there are almost no fixed gear riders, no velodrome or riding track and almost no track parts available is a little tough to get answers. I have to mail order in the hubs, cranks, cog, lockring and crank (so far) to build up the frame. That or get the only track gruppo available here... Dura-Ace.

Mr. Shadow

As long as it's a straight chainline it should work fine.
I recently had an IRO hubbed wheel built up and it's wonderful.

dubteka

the two standward bb witdths are 68mm (english) and 70mm(italian)...((then theres french, etc...) so depending on your frame, you should use the correct one, cause the other wont work!

what you need to be concerned with for chainline is the spindle length... depending on what cranks you have and what rear hubs you have, you need to get the according spindle length for the bb. standard seems to be about 111mm.. but depends on the entire setup. theres a wide number of spindle lengths available in all threadings of bb's. i used a 111bb on a 126 rear spaced frame, and it worked fine.

go here for some info: https://www.sheldonbrown.com/chainline/

good luck.

wilcru

No. A 109mm spindle is an 109mm spindle. The spindle length is not affected by the BB's shell size.
The Sugino 75 BB is for 68mm shells, and has a 109mm spindle.
I'd either buy a Shimano UN73 73x110mm and trade its "cups" for some Phil Wood Bottom Bracket Cups (that'll allow you to adjust your chainline), or I'd just go ahead and shell out for a 108mm Phil BB.

* jack *

Be careful - depending on the frame, if you find a certain spindle length that would give you 'good' chainline,
that might result in moving the chainring too close to the chainstay.

peripatetic

You might want to post a similar thread in the 'Mechanics' section, and maybe also email sheldon brown directly (try a members search in this forum.)

Tough situation you're in, but as with all things fixed, eventually fix-able.

njwbert

Thanks for the advice. That removed the migraine.

Now I can go ahead and order online with confidence.

I will be thnking of other alternatives before the phil woods as my bike shop does not have the phill wood tools. Or would the regular park tools work as well?

njwbert

I just received my order from Business Cycles today. Whoo hoo! All I need are the remaining stuff I ordered from Sheldon Brown and I can finally build up the bike.

Plus I am very happy. For an international order it took only 6 days to arrive. Great stuff. Prompt! Definitely two thumbs up and will order from them again.

* jack *

Good to hear. Post some photos for us.

njwbert

Now I have a choice of old rims from my friend. What should i take?

1) single wall araya rims (pair)

2) mavic MA2 (pair)

3) one campagnolo omicron (rear) and one mavic ma3 (front)

jim-bob

MA-2s have always been good to me.

njwbert

Yay my IRO hubs have arrived from Harris Cyclery! Cheers Sheldon!

Okay I have used the Rinard spoke excel spreadsheet to calculate the length and i got 298 mm which looked a little weird. Searching for posts of people who used the same build yielded a value of 294 mm though the rear hub spacing was not specified.

My choice is the IRO fixed/fixed rear hub (respaced to 126mm) and front hub. Laced 3x for both front and rear to Mavic MA-2 rims. What spoke length would I need? Anyone here did the same build?

njwbert

My fixed gear bicycle is finally up! Picture is posted in the picture sticky.