9/2/14 2:49 PM

I know it is only 2.5mm wider than a 130 spaced road frame from center per side. But the cross chaining dynamic is noticeably different. Wondering if the Triple 6703 cranks and chainline might be more co-operative. The 34 Compact cranks are not doing well, where as the 39/53 did not mind as much.

Next, BB7 caliper and 135 spacing makes for caliper heel strikes. Heel hits the arm and pushes in the outer pad on occasion.

Folks with smaller than a 46-7 shoe and same chainstay length may be non issue.

But the center screw for the adjustment wheel may be tearing up your shoe, well mine being a 47. It looks like it could. But no cuts on shoe so far, maybe the shoe is hitting the actuation arm short of the screw. I tilted my cleats [put on new ones] and
test rode it, did not hit it. In the 30 mile ride on Sunday I kept all of a sudden hearing disc noise out of now where every now and then. 5-6 times in 30 miles. new bike new noises, figured out what it was finally when I shifter my weight which rotated my left heel in and I felt it touch.

Thinking of bringing it back for a solution. The TRPs are a lot narrow due to the way they are built, maybe that is why they used them.

Also wondering if the wider Q factor of the triple 6703 cranks might make it a little better too.

The 130 spaced Lemond Proprad with the BB7s I do not recall hitting my heel. Nor if the older BB7 was a bit different as far as the profile.

9/2/14 3:00 PM

Strange, there are 2.9 bazillion MTBs rolling with 135 spacing and they don't have issues, no matter the front chainring count. The spacing of the rear has nothing to do with the q factor which is really why you would have heel strikes on a 135 spaced rear end. Unless that brake caliper sticks out like all get out. That does not bode well for aero concerns on a road bike.

9/2/14 3:11 PM

Because road 2x cranks have smaller/tighter chainline center.

Example; my Gary 29er is 2" center of seat tube to the center ring on the triple.

The Roubaix with Compact road crank has the big ring less than 2: from center of seatube.

The middle ring on my 6703 10 speed triple on the old Roubaix is 1-7/8" from the center of the seatube.

A triple road crank might make thing play nicer on the 135 rear with road cranks.

The original plan was to put the 6703 on the diasc Roubaix. But I had too many loose D/A 10 speed parts form converting the Strong to SS and may have got ahead of myself a little.

As far as heel clearance, the 29er chain stays are like 12' long compared to the Roubaix. ;)

9/2/14 3:12 PM

The chainstays are longer on a mtb, which softens the angle for cross chaining and may allow more heel clearance.

How long are the chainstays on your new Roubaix, Sparky?

9/2/14 3:22 PM

"The spacing of the rear has nothing to do with the q factor"

Consider that statement backwards. ;) The Q-factor on my 6703 cranks is near 12mm wider than the compact 2x crank. That would put my heel 6 mm further from the caliper, yes?

EDIT
True Dat on the shallower angle 12 miles back from the BB. ;)


Comparatively, center of rear caliper piston on my GarFish 29er is over 3" further away from BB than on the Road disc Roubaix. It is also above the seat stay, and the Roubaix caliper is between the seat and chain stay.

9/5/14 3:05 PM

Heel strike is also affected by things such as dropout style - breezer dropouts put the rear end of each chainstay almost 10mm further from the centreline of the bike than the older style dropout where the tang on the dropout bisects the end of the chainstay. This is a considerably greater difference than the 2.5mm extra you get going from 130mm to 135mm.

I ride with my heels in, and on the couple of custom frames I have where the builder used breezer dropouts, I got them to S-bend the chainstays so that I wouldn't have problems with heel strike. Compare these two frames - both 135mm rear spacing, but I would get heel strike on the Ti frame with the breezer dropouts if the chainstays didn't have the S-bend:

9/5/14 4:21 PM

I like the Stove pipe seat stays on the Ti Frame. ;)

See your point of course on the dropouts..


Turns out the BB7 rear is a real issue, heel strike city. Forget the drop outs...

LBS has ordered the TRP Spyres, taking the BB7s off and asked I pay 30.00 charge. But they would not ask for anything if it not the outlet store. Seems fair. They are almost an 1" narrower and the outer BB7 adj wheel is way past the center line. The TRPs are symmetrical as far as width from centerline [disc].