Mini V help

[coffeecherrypie]

I’m running TRP 8.4s on an AlphaQ CX fork (paceline classifieds shoutout). Brake lever is 9-speed Sora aka R2000. I have to set the pads up with like 1 mm clearance to the rim and I’m still almost bottoming out the lever before I can lock up the wheel. The pads are at the bottom of the slots with this fork. Could it be that I’ve done something wrong with the setup—or is it just how it’s going to be with this combination of brake/fork/lever?

[rowebr]

Did you ride the bike around the block to test the brakes yet?

Also, what is the external diameter of your rim there?

[coffeecherrypie]

Originally Posted by rowebr

Did you ride the bike around the block to test the brakes yet?

Also, what is the external diameter of your rim there?

I’ve ridden the bike for maybe 100 mixed road and gravel miles with this setup. It bugs me but it’s not a showstopper at the moment. I should have stated in the OP, the rims are A23s which have an external width of 23mm.

[MikeD]

Probably your brake levers have too much leverage (pull too little cable) for these brakes if you're bottoming the lever against the bar. You might try a Travel Agent.

Also, if you don't have much stopping power, you should clean your pads and rims with acetone and maybe a ScotchBrite pad. KoolStop pads might stop better too. Stock Tektro/TRP pads kinda suck, IMO.

[coffeecherrypie]

Originally Posted by MikeD

Probably your brake levers have too much leverage (pull too little cable) for these brakes if you're bottoming the lever against the bar. You might try a Travel Agent.

Also, if you don't have much stopping power, you should clean your pads and rims with acetone and maybe a ScotchBrite pad. KoolStop pads might stop better too. Stock Tektro/TRP pads kinda suck, IMO.

Good thoughts, thanks.

I should note that I don’t have this issue in the rear, where the pads are higher in the slots.

[SDJ]

Wasn’t the 8.4 better suited for campa? (Run them myself)

And for Shimano levers there was another model with longer arms at like 90mm instead of 84mm (hence 8.4)

But am not certain

Edit: found some additional info on roadbikereview
"The majority of people’s opinions is that the CX9 is best paired with the new Shimano such as 7900, 6700, and 5700. The 8.4 best paired with Sram, Campy and older Shimano. You can go either way but you do get a smidge of extra rim clearance with the 8.4 and really don’t lose any power. Both are going to be a ton more powerful than a traditional cantilever."

[rowebr]

Originally Posted by coffeecherrypie

I’ve ridden the bike for maybe 100 mixed road and gravel miles with this setup. It bugs me but it’s not a showstopper at the moment. I should have stated in the OP, the rims are A23s which have an external width of 23mm.

Gotcha. From your photo I think you have the spacer placement correct for the wide rims, and since the brakes work better on the rear where the pads are above the bottom of the slots…ugh this may be the best you can do. Never used a problem solver to adjust the brake pull but that sounds like a good idea to try.

[tellyho]

I rode these on wide rims (Pacenti) for a long time and found the setup best with a travel agent. Not aesthetically, of course - I hate the way they look- but stopping power was unbelievable.

I wonder if getting the arms more vertical by using koolstop thinlines might make a difference?

[C40_guy]

Have you tried moving the pad mounting points higher up in the caliper slot?

[jds108]

Those posts are really low in the arms. So yeah, you're getting a lot of leverage but very little pad travel. I think you're going to need a travel agent. (and will probably need one regardless of which v-brake you use with this fork.)

[brakecheck]

Yes + 2 on swapping the spacers on the brake pads .
It will bring the arms out wider . And keep the arms square when applying brakes.
Cheers

[Mark McM]

Originally Posted by jds108

Those posts are really low in the arms. So yeah, you're getting a lot of leverage but very little pad travel. I think you're going to need a travel agent. (and will probably need one regardless of which v-brake you use with this fork.)

Looking at the photo, I tend to agree with this. Leverage is a matter of geometry, so the solution is to make a change in the geometry somewhere. The brake studs are where the are, so they can't be changed. And changing the leverage of the levers isn't practical. Shorter V-brake arms would help, but you've already got very short ones. So, the most practical solution is a cable travel converter (i.e a Travel Agent).

[Mark McM]

Originally Posted by C40_guy

Have you tried moving the pad mounting points higher up in the caliper slot?

Originally Posted by brakecheck

Yes + 2 on swapping the spacers on the brake pads .
It will bring the arms out wider . And keep the arms square when applying brakes.

I fear these will make little difference. Moving the pad mounting points on the slots in the arms won't matter, as the important dimension is the height that the pads contact the rim's brake track (and you can't change the height of the brake tracks). Swapping spacers on the pad mounting bolts may move the arms a little bit in or out, but it will only have a small effect on the vertical height of the arms - the leverage will depend on the perpendicular distance from the cable to the pivot, and moving the arms a little inward or outward will have only a small effect on the the perpendicular distance.

[coffeecherrypie]

Originally Posted by SDJ

Wasn’t the 8.4 better suited for campa? (Run them myself)

And for Shimano levers there was another model with longer arms at like 90mm instead of 84mm (hence 8.4)

But am not certain

Edit: found some additional info on roadbikereview
"The majority of people’s opinions is that the CX9 is best paired with the new Shimano such as 7900, 6700, and 5700. The 8.4 best paired with Sram, Campy and older Shimano. You can go either way but you do get a smidge of extra rim clearance with the 8.4 and really don’t lose any power. Both are going to be a ton more powerful than a traditional cantilever."

Thanks but hrm I do wonder if that is still accurate, didn't the Shimano brake pull change again with 11-speed?

[coffeecherrypie]

Originally Posted by jds108

Those posts are really low in the arms. So yeah, you're getting a lot of leverage but very little pad travel. I think you're going to need a travel agent. (and will probably need one regardless of which v-brake you use with this fork.)

Originally Posted by tellyho

I rode these on wide rims (Pacenti) for a long time and found the setup best with a travel agent. Not aesthetically, of course - I hate the way they look- but stopping power was unbelievable.

I wonder if getting the arms more vertical by using koolstop thinlines might make a difference?

Originally Posted by brakecheck

Yes + 2 on swapping the spacers on the brake pads .
It will bring the arms out wider . And keep the arms square when applying brakes.
Cheers

Originally Posted by Mark McM

Looking at the photo, I tend to agree with this. Leverage is a matter of geometry, so the solution is to make a change in the geometry somewhere. The brake studs are where the are, so they can't be changed. And changing the leverage of the levers isn't practical. Shorter V-brake arms would help, but you've already got very short ones. So, the most practical solution is a cable travel converter (i.e a Travel Agent).

Thanks much for the thoughts, everyone. It seems like the consensus is that a travel agent is likely necessary--I'll do that if I have to.

Interesting that there are two opposite suggestions, swap the spacers to push the arms out wider, and use thinlines to bring the arms in. I may try both. If I had to guess which one might work, the thinline approach does make some sense to me: as the lever is pulled the pads move downwards some in addition to inwards, so I think thinner pads would let me place the pads higher in the slots, which would maybe get at the root of the issue.