campagnolo bottom bracket question

just taken out a 117mm shimano BB out of my holdsworth and want to replace it with a campag one.
does anyone know what length axle i need to run it with a gran sport chainring?
i'm guessing on 111mm.....

Search for the transmission database. There may be an answer in there.

Search for the transmission database. There may be an answer in there.

ok, not seen that one before - thank you

velobase says 120mm
http://velobase.com/ViewComponent.aspx?ID=df8b9ad3-4872-48ff-ac3e-cf96516ad7c4&Enum=115

velobase says 120mm
http://velobase.com/ViewComponent.aspx?ID=df8b9ad3-4872-48ff-ac3e-cf96516ad7c4&Enum=115

i found campagnolo "strada" on the transmission database 111mm. isn't strada "road"?
anyway 120mm might explain why i had a 117mm shimano BB fitted.
come to think of it i tried to fit the GS on my other holdsworth that had a 111 fitted years ago and it "just didn't fit"

thanks hilly ben

Have you seen this? If I've done my sums correctly, then "old style" BB were 111mm and "new style" 113.5mm.

I wonder if the VB contributor confused the marking on the axle: "120" refers to the rear spacing and not the BB.

The Shimano BB you were using would equate to 119mm ISO: what was the gap twixt ring and stay like?

nuovo record should be a 112 on 68

so yes 120 seems weirdly long for the GS which ought to be the same as record

That scan says 110mm (old) and 112.5mm (new).

Is 1978 when "old" became "new"?

Enjoying a custard cream as I write.

chart beats velobase

a festive thanks for your help.
from memory (i took the cranks and bb off on sunday) the distance to the ring was about 8mm (thats with my 130mm oln rear wheel in place)
i had the ring on the inner side of the spider and now want to put it onto the outside so it looks as it should.
just to check i've added pictures of the cranks (so hopefully i'm not talking utter bollocks, like usual)
i think that it's a 1984 model and the GS that is stamped is for gran sport?
it was my first SS conversion so i was until now running it with a 120mm oln rear, and having a "spare set" of campag record hubs on the omega rims thought i'd use those instead.

heres the build
http://www.lfgss.com/thread119428.html

2 Attachments

Have you seen this? If I've done my sums correctly, then "old style" BB were 111mm and "new style" 113.5mm.

I wonder if the VB contributor confused the marking on the axle: "120" refers to the rear spacing and not the BB.

The Shimano BB you were using would equate to 119mm ISO: what was the gap twixt ring and stay like?

yes i agree with your calculations too.

The Shimano BB you were using, would equate to 119mm ISO. An 8mm gap between the ring and the chainstay sounds about right, if you should have been using 111mm or 113.5mm.

If you are riding this SS (rather than as a double), then this complicates things slightly. You'll want to move the chainring inboard to the same position that the spider would occupy with the "correct" BB: something like 1.5/2.0mm.

Assuming you have "new" cranks, then the correct BB is 113.5mm, so a 111mm one should work.

This is handy as Campag used 111mm for all doubles from C-Record, right through to Ultra Torque (except Record and Chorus which went to 102mm from 1995), so they are plentiful and relatively cheap.

If 111m isn't enough, then the next one down is 109mm which was used by Triomphe/Victory and Record Pista: not so readily available but about the same price (apart from Pista obviously).

If 109mm is too much then some BB spacers from Velosolo will allow you to tweak the chainline.

What sort of freewheel are you using: screw-on or a converted freehub?

What sort of freewheel are you using: screw-on or a converted freehub?

i'm using an 8 speed freehub with a spacer kit.
i'll see if anyone in the cambridge area has a 111mm BB and i'll try it to prove the very good theory of yours first.

thanks for taking the time to help :o)

Most welcome.

Using a converted freehub makes things easier, as you have much more leeway to tune the chainline at the rear.

If you're using a kit with two large spacers, you may want to get a pack of spacers from Velosolo, as they will give you more flexibility.

If you stick whatever BB you have back in, you can measure the gap between the spider and chainstay accurately.

You'll then have a better idea of what size BB will work.

i've quickly screwed the shimano BB in drive side, attached the crank and fitted the rear wheel to take some measurements and taken a few photos....
from the stay to the spider it's about 5mm, and from the stay to the chainring about 10mm.
as it is the chainline seems to be pretty straight

just googled sheldon browns website:
If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length.

so 111mm may be fine then, i 'll try and borrow one to see if it fits...

3 Attachments

First a couple of links which I couldn't give you before via my phone:

• hub spacers (top of the page)
  
• BB spacers (scroll down to the bottom of the page)
  
  

Sheldon is wrong about JIS/ISO BB, as the forum's own MDCC_Tester explains.

In short, the difference is in how the BB is measured: JIS are measured to the bottom of the chamfer and ISO end-to-end. In practice this means that a JIS BB is the same as an 2mm longer ISO one, ie JIS 109mm = ISO 111mm.

So the 117mm Shimano that you have is the same as a 119mm Campag, which ties-in with the measurements you've taken and the recommended BB for your cranks.

Based on what you've written, my guess is that 111mm ISO will be a little too much, but close enough that a BB spacer would sort it.

I don't know how close Sawston is to you, but that's the lair of Marxist_Vulcan: he has a sizeable parts bin, knows his onions and is a decent sort to boot, so I'd give him a shout.

leon is about half a mile away, we've shared the odd ride......thanks for your help especially over the festive period.
not sure what i will do tbh but i'll give leon a shout

problem sorted...i now have a chorus carbon chainset and matching axle, so i'll just use my 111mm axle that i'm going to replace and stick it in the holdsworth

or not.....damn it got the BB swapped into the holdsworth and bolted the cranks on but the drive side spider is literally 2mm from the stay.
is 2mm ok? i'll try and take a photo...but thinking i could put a BB spacer in just to add a bit more clearance

1 Attachment

Running doubles as a single is a compromise: there is no "ideal", because what you're doing is "wrong" from the outset.

If you're worried about flex when you "pull the pin" and establish a break to give your sponsors more airtime, then you could use a spacer, but if your chainline is good I'd be ok with that.

HTH! :)

thanks again for your advise, i'll give it a go as it is, if it rubs i should be able to spot it....

actually i've used the grinder and taken a few mm off the back of the spider - sacrilege i know. just need to sort out a singlespeed kit and i'm away

What rear wheel are you using, Shimano freehub? I've got SS sprockets and spacers.

What rear wheel are you using, Shimano freehub? I've got SS sprockets and spacers.

using a record 8 speed hub with campagnolo omega rims (just happen to have a spare pair).
thanks for the offer, but would shimano fit?