Mtb groupset on "road" bike.

General cycling advice ( NOT technical ! )
djnotts
Posts: 3036
Joined: 26 May 2008, 12:51pm
Location: Nottingham

Re: Mtb groupset on "road" bike.

Post by djnotts »

"As far as the OP's bike I'd try road flat bar shifters before mucking about with mtb chainline and gearing."

"I went that route on a past bike. I found that the pressure required to shift the front road mech was too much for my thumbs so I changed to drop bars (different bike)."

I am running flat bar road shifters and yes front shifter not kind on my weak left wrist. But nor are drop STIs. On my Giant Anyroad I have ditched the triple front STI and fitted an ancient Suntour barcon.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Mtb groupset on "road" bike.

Post by gregoryoftours »

CinnabarMoth wrote: 3 Dec 2021, 10:58pm
gregoryoftours wrote: 3 Dec 2021, 6:58pm 'If the pads move ok and contact the disc then I struggle to imagine why there should be something wrong with the braking mechanism?'

The tolerances are pretty poor in an unacceptably high proportion of trp Spyres in my experience. The pads move no problem, but they aren't properly parallel to the rotor or each other as they meet which results in bad performance. It improves a little bit not a lot as the pads wear unevenly to conform to the rotor surface.
Not sure if this is connected to the problem you outline but the instructions for mounting my Spyke callipers require the bolts to be loose
enough to allow some play in the calliper, the break lever is then pulled firmly enough to clamp the pads hard (and presumably flat ) on the disk and while still squeezing the brake lever the calliper mounting bolts are tightened, this ensures that whatever possition the pads may start out in while in the open position they will be flat to the disc when closed.
No idea if this is the same with Spyres but on the Spikes there is also the facility to micro adjust the possition of each pad independently.
Clamping the brake on the rotor before tightening the bolts can help to align the caliper and centre the rotor between the pads.

Avid disc brakes have more adjustment in this regard because they use dish/dome washers around the caliper like v brake pads, so some amount of additional angle adjustment is available to those brakes that can be helpful given a badly faced disc mount.

The problem that I've seen with quite a few of the TRP mechanical calipers is that the pistons/pads are not parallel to each other due to bad manufacture. No amount of adjustment can rectify that because at best only one pad can be set up parallel to the rotor, the other one will be off.
djnotts
Posts: 3036
Joined: 26 May 2008, 12:51pm
Location: Nottingham

Re: Mtb groupset on "road" bike.

Post by djnotts »

"The problem that I've seen with quite a few of the TRP mechanical calipers is that the pistons/pads are not parallel to each other due to bad manufacture. No amount of adjustment can rectify that because at best only one pad can be set up parallel to the rotor, the other one will be off."

Having examined the one I removed a simple visual check, including the wear pattern of the pads, would support the above.

My cheap copy version will lock the rear wheel, no chance with the Spyre.
CinnabarMoth
Posts: 50
Joined: 5 Nov 2021, 7:46am

Re: Mtb groupset on "road" bike.

Post by CinnabarMoth »

djnotts wrote: 8 Dec 2021, 8:48pm "The problem that I've seen with quite a few of the TRP mechanical calipers is that the pistons/pads are not parallel to each other due to bad manufacture. No amount of adjustment can rectify that because at best only one pad can be set up parallel to the rotor, the other one will be off."

Having examined the one I removed a simple visual check, including the wear pattern of the pads, would support the above.

My cheap copy version will lock the rear wheel, no chance with the Spyre.
I have two of them and they are both fine.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Mtb groupset on "road" bike.

Post by gregoryoftours »

Yes they're not all bad by any means but in my experience an unacceptably high proportion of the ones owned by me/friends/colleagues have been.
djnotts
Posts: 3036
Joined: 26 May 2008, 12:51pm
Location: Nottingham

Re: Mtb groupset on "road" bike.

Post by djnotts »

gregoryoftours wrote: 9 Dec 2021, 8:14pm Yes they're not all bad by any means but in my experience an unacceptably high proportion of them are.
When I was attempting to "sort" mine I read many dozens of comments, user reviews etc and reached precisely this conclusion. The fact that the cheaper copy performs significantly better only reinforces it.
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