Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Bicycle Mechanics (https://www.bikeforums.net/forumdisplay.php?f=10)
-   -   Campagnolo Racing T Crank Bottom Bracket Puzzler (https://www.bikeforums.net/showthread.php?t=1146948)

H5N1 06-15-18 06:02 AM

Campagnolo Racing T Crank Bottom Bracket Puzzler
 
I’m feeling bothered about a Campagnolo Racing T triple crankset installation.
It’s a square taper ISO crank, and the recommended Bottom bracket is a Campagnolo Centaur 68 X 115.5 cartridge.
With the bottom bracket and crankarms installed, the entire unit is shifted about 5-7mm toward the drive side.
I read some older discussions on the forum with regard to the Racing T triple and discussions about needing an assymetric bottom bracket, and that seems to be what this installation calls for.
I welcome your questions, comments and suggestions.

fietsbob 06-15-18 10:17 AM

I have a racing T (on 3* bikes) 111 symmetrical is for 1.125" seat tubes , 115.5 is for oversize seat tubes (31.8~35)
the extra 4.5 [/2 2.25 per side] is because the FD is moved outboard.. so derailleur swing moves with it

*2 Brit thd, 1 Italian* ,all 3 steel frames 28.6mm/1.125" seat tubes..

A Phil BB , can, be because of the design, user changing the offset...
the spindle is smooth, relies on precise fit with the bearings , but can be pulled through .

Read that the Record Triple Square taper BB was not symmetrical ,
but know nothing more..

* I have an un needed italian thread 115.5 to sell.. [pm]





..




....

Andrew R Stewart 06-15-18 03:53 PM

Asymmetrical BB spindles usually have the extra length on the drive side, to better locate the rings to not scrape on the chain stays. But the OP suggests that he might need a asymmetrical spindle off set to the non drive side. Not common in "factory assembled "cartridge" BBs.

So I suggest doing actual measurements of current chain line, spindle length and centering offset (if any) and determine about how much closer into the frame both crank arms (and rings) can be and still leave a few MMs of clearance. Then do the math. How much change to get the ideal chain line? Will this result in ring or arm contact with the stays? Is this BB spindle set up available? Where are you willing to compromise? Cost, dimensional results? Andy

H5N1 06-16-18 04:19 AM

It seems to have something to do with this particular crankset, ie. the Racing T triple.
The bike is a Black Mountain Cycles road bike. 28.6 tubing, not oversize. 68mm bottom bracket shell, English thread.
It's usually set up with a Sachs New Success (re-branded Campy Chorus) and a 68X107mm JIS cartridge bottom bracket.
There's no problem with this setup (chainline is good, but I don't recall the numbers), but if I plop the triple onto the 68x107 JIS bb, I get the same result:
Everything is shifted toward the drive side by about 5-7mm.
I've seen other threads where an "adjustable" bottom bracket was used with the Racing T crank.
I'm told that Phil Wood makes one. I was put off by the expense, but would consider doing that to get a liveable result.

Addendum:
It looks like Miche makes an adjustable cup bb, and I already have the installation tool I need. 68x107 ISO would be too short, though. My current Campy Centaur 68x 115.5 ISO is a perfect fit save for the offset problem.

H5N1 03-25-19 08:11 AM

Well,
I'm back and more perplexed than before.
I will confirm that with a Campy Centaur 68x155.5 BB, the crankarm-chainstay gap is significantly wider on the drive side than on the non-drive side!
Worse than that, I've repeated this experiment by purchasing ANOTHER Campy Racing T in 170mm crankarm length, and the results are identical: The data is in and it's a very robust finding.
Ok, what the hell is going on here, and which assymetric BB (shorter on the drive side) is going to work?

fietsbob 03-25-19 09:34 AM

A Phil Wood BB, the current offerings, you can pull the spindle through the bearing ( accurate press fit ) by hand..

and dial in the relative offset , yourself.. I have done so , myself

2 mounting ring tools stacked, a flat washer , the crank bolt & 2 wrenches 1 holds the axle , 1 turns the bolt..






....

DaveSSS 03-26-19 08:52 AM

Post your question on the paceline forum. Old Potatoe probably knows the answer to your problem.

H5N1 03-27-19 08:00 PM

Ok,
I'll give that a go.

AJI125 02-07-20 08:46 AM

Sorry for the Zombie thread revival. But I was looking for a little info on a Racing T (considering picking one up) and was hoping you solved your problem. I've got this page from the 1998 Manual that just confirms what others have said. 111mm for smaller seat tubes, 115.5 for larger, and symmetrical. At this time Athena was 9 speed, I'm not finding anything older in my (incomplete) copies of things.

https://cimg3.ibsrv.net/gimg/bikefor...99bd3e723c.jpg

Road Fan 02-09-20 09:44 PM


Originally Posted by H5N1 (Post 20853837)
Well,
I'm back and more perplexed than before.
I will confirm that with a Campy Centaur 68x155.5 BB, the crankarm-chainstay gap is significantly wider on the drive side than on the non-drive side!
Worse than that, I've repeated this experiment by purchasing ANOTHER Campy Racing T in 170mm crankarm length, and the results are identical: The data is in and it's a very robust finding.
Ok, what the hell is going on here, and which assymetric BB (shorter on the drive side) is going to work?

Just realized this is a zombie thread, so apologies to the Thread Starter, who probably no longer needs an example. But I think it's a worthwhile example for others dealing with the oddities of triples and the "fitting" of replacement BBs. Additional general information can be found in Sutherland's Fifth and in Barnett's.

I don't see a problem, necessarily. I've had a number of Campy doubles install (with the BBs originally supplied or recommended by Campy) with the crankarms evenly spaced from the chainstays, and with correct chainline - Nuovo Record, the first "streamlined" Record, first generation 1995 Chorus, several Centaur square-taper and Power-torque compacts, and a couple of carbon Records. I don't generally expect the Triples to install the same way. I have a Racing T on Mrs. Road Fan's Georgena Terry road bike. I will post the Q-factor, front chainline, rear chainline, chainstay clearance to crank arm left and right, and chainring clearance to the drive-side chainstay. You may want the narrowest possible Q and left-right pedal balance, but it just might not be possible with either BB. There are too many reasons why a BB and chainset may not fit right, that i think we simply need to look at the key dimensions of your installation and see which of the two satisfies the critical points and does not not terribly mess up the non-critical points. I want to do this to illustrate that sometimes what you have is the best you can practically get. I suggest making these same measurements and seeing if you have any available degrees of freedom.

INSTALLATION OF RacingT on Mrs. Road Fan's Terry:

Q-factor, 155 mm
Front chainline, 46 mm
Rear chainline, 43 mm
Chainstay clearance to crank arm left, 9.5 mm
Chainstay clearance to crank arm right, 18.2 mm
Chainring clearance to chainstay, 1 mm (small chainring)

I'm pretty sure my BB is the 115 mm Centaur model.

In my case the left and right crank arm clearances are wildly mismatched, 18 mm on the right and 9.5 mm on the left (non-drive side). No complaints about this from Mrs. Road Fan, so it's not a problem. Same for the mismatch between the front and rear chainlines. Q-factor is better than many other triples, if I measured it right, but not as good as many Campy doubles. nonetheless it would seem nice to try the 111 mm BB perhaps with a 1 mm drive side shim under the right cup.

HOWEVER, there is only 1 mm clearance between my small chainring and the painted chainstay! So there is zero margin to move the chainset closer to the centerline of the frame. This installation cannot be better aligned. Campagnolo designed a functional triple chainset, but did not solve all the potential problems.

To be fair, this Terry frame doesn't have any dimples on the chainstay, for whatever reason - it could have determined to be that way by Ms. Terry, or it could have been an implementation decision by Wilier, who actually built these frames. But having installed this chainset on this frame, my installation is about as good as it can get.

H5N1 02-10-20 07:32 PM

The Proposition Will Be Tested
 
No apologies needed. The thread has laid fallow for a while, and that has allowed some time for info like yours to come in, which is great.
I just ordered a Phil Wood bottom bracket, which should be here next week. It should have enough lateral adjustment available to solve this vexing issue. Stay tuned.




Originally Posted by Road Fan (Post 21321416)
Just realized this is a zombie thread, so apologies to the Thread Starter, who probably no longer needs an example. But I think it's a worthwhile example for others dealing with the oddities of triples and the "fitting" of replacement BBs. Additional general information can be found in Sutherland's Fifth and in Barnett's.

I don't see a problem, necessarily. I've had a number of Campy doubles install (with the BBs originally supplied or recommended by Campy) with the crankarms evenly spaced from the chainstays, and with correct chainline - Nuovo Record, the first "streamlined" Record, first generation 1995 Chorus, several Centaur square-taper and Power-torque compacts, and a couple of carbon Records. I don't generally expect the Triples to install the same way. I have a Racing T on Mrs. Road Fan's Georgena Terry road bike. I will post the Q-factor, front chainline, rear chainline, chainstay clearance to crank arm left and right, and chainring clearance to the drive-side chainstay. You may want the narrowest possible Q and left-right pedal balance, but it just might not be possible with either BB. There are too many reasons why a BB and chainset may not fit right, that i think we simply need to look at the key dimensions of your installation and see which of the two satisfies the critical points and does not not terribly mess up the non-critical points. I want to do this to illustrate that sometimes what you have is the best you can practically get. I suggest making these same measurements and seeing if you have any available degrees of freedom.

INSTALLATION OF RacingT on Mrs. Road Fan's Terry:

Q-factor, 155 mm
Front chainline, 46 mm
Rear chainline, 43 mm
Chainstay clearance to crank arm left, 9.5 mm
Chainstay clearance to crank arm right, 18.2 mm
Chainring clearance to chainstay, 1 mm (small chainring)

I'm pretty sure my BB is the 115 mm Centaur model.

In my case the left and right crank arm clearances are wildly mismatched, 18 mm on the right and 9.5 mm on the left (non-drive side). No complaints about this from Mrs. Road Fan, so it's not a problem. Same for the mismatch between the front and rear chainlines. Q-factor is better than many other triples, if I measured it right, but not as good as many Campy doubles. nonetheless it would seem nice to try the 111 mm BB perhaps with a 1 mm drive side shim under the right cup.

HOWEVER, there is only 1 mm clearance between my small chainring and the painted chainstay! So there is zero margin to move the chainset closer to the centerline of the frame. This installation cannot be better aligned. Campagnolo designed a functional triple chainset, but did not solve all the potential problems.

To be fair, this Terry frame doesn't have any dimples on the chainstay, for whatever reason - it could have determined to be that way by Ms. Terry, or it could have been an implementation decision by Wilier, who actually built these frames. But having installed this chainset on this frame, my installation is about as good as it can get.


Wildwood 02-11-20 01:45 PM

I have RacingT 9 and CompTriple10 with symmetric axles - and when I first get on those bikes the wide Q-factor is noticeable. I always think my knees or ankles or hips will hurt, but nothing bad seems attributable to the slightly 'wider stance'.

Road Fan 02-11-20 08:45 PM


Originally Posted by H5N1 (Post 21322841)
No apologies needed. The thread has laid fallow for a while, and that has allowed some time for info like yours to come in, which is great.
I just ordered a Phil Wood bottom bracket, which should be here next week. It should have enough lateral adjustment available to solve this vexing issue. Stay tuned.

H5N1, thanks for the appreciation and kind words! But, on my wife's frame a BB with a shorter right-end length (called SER for "side-end right) will not help to move the right crank arm/spider toward the center of the bike because my chainrings will hit the frame. I haven't looked yet at all the current postings in the thread - have you replicated my measurements? How much room do you have between the closest part of the chainrings or bolts, and the chainstay? That is what you have to work with. With that frame and chainset you might be limited, as is my setup for Mrs. Road Fan's bike.

Road Fan 02-11-20 09:49 PM


Originally Posted by Wildwood (Post 21323838)
I have RacingT 9 and CompTriple10 with symmetric axles - and when I first get on those bikes the wide Q-factor is noticeable. I always think my knees or ankles or hips will hurt, but nothing bad seems attributable to the slightly 'wider stance'.

The RTs are inherently wide cranks for sure. I've never had a Comp Triple. It was said to be Record grade, FWIW. Wide Q doesn't cause me much discomfort or pain, but with low Q (such as the 140 to 145 mm of a Record double or a vintage Chorus double, I spin well and more freely than with a wide stance. So I have at least a comfort preference for low Q.

Road Fan 02-12-20 03:58 AM

In this re-awakened zombie thread https://www.bikeforums.net/bicycle-m...placement.html is the information that Token has or had a 115 mm ISO taper BB, 115 mm with a longer right spindle, intended for Campagnolo triples such as the Racing Triple. Token would be worth looking at for other Campy replacements. I know I used to see them on Ebay.

HillRider 02-12-20 07:10 AM

Unless you already have the Racing Triple crank, I recommend looking for a more modern but currently out of production Chorus Triple crank. I had one from 2006 installed on a Litespeed Tuscany using the matching Chorus/Record 111 mm Asymmetrical bottom bracket. This combination worked extremely well.


All times are GMT -6. The time now is 02:39 PM.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.