Question about v-brake

[coldriverjoe]

Hi! I'm new to trials (and to the forum). I bought a used Inspired Element 24" (I think it's 2012 or 2013) about a month and a half ago and have been practicing the basics. I'm hooked! For context, I'm 41 and have been mountain biking for about 15 years. Oh also I live in the US (Connecticut).

I'm starting to learn to hop on my back wheel and I'm finding that I have to squeeze the brake lever really hard to get a good bite. If I transition from endo to back wheel it's not too bad because I can pre-lock the rear brake and maintain bite, but I don't feel like I'm getting a solid bite when I try a pedal-up to back wheel. It feels like instead of getting an "instant" lock, there is a certain amount of decelerating travel that the wheel goes through. As a beginner, I don't know if that's just the name of the game, or whether the brakes should get a tune up or upgrade in order to grab more instantly. After a session, my forearms are toast from squeezing the brake levers. 

This brake has cable-actuated v-brakes in the rear. The v brakes are Avid Single Digit 5 and the lever is a Shimano XTR (pictures attached). I don't know anything about the condition of the brake pads. But even just squeezing the lever to produce travel of the pads takes quite a bit of force - something very unfamiliar coming from hydraulic disc brakes in my MTB.

Also, I've been reading about grinding the rim to produce better bite. Not sure if this is something that I should consider but the rim is completely smooth.

So I guess to summarize:

1) Hello!

2) Should I expect a more "instant" lock from my rear brake?

3) Should I expect brake levers in my trials bike to require so much more finger force than what I'm used to in a MTB?

3) Does my setup seem appropriate? (I haven't found much about the Avid Single Digit 5 out there, and a search in these forums produced zero results)

4) Any tune-up / upgrade that I should consider? Grinding the rim? New brake pads? Replacing cable-actuated with hydraulic vees?

Thanks for any feedback and sorry for the long post!

[Ali C]

Welcome!

Not a bad bike to start on and you're never too old to benefit from starting trials.

So obviously there are other brakes that are more popular for trials (disc for street, hydro rim for comps) but a well set up V-brake can compete (and sometimes be better (my brake of choice for comps is a V-Brake)) with the best.

The first thing I notice is you're using standard pads on a smooth rim. This is great for modulation and is quiet but will reduce bite. You have two options that will really help get the bite you're looking for:

1) Upgrade the pads to something with more grip on smooth rims. Many brands make suitable pads and they are often the same thing just repackaged. https://www.tartybikes.co.uk/vbrake_pads/jitsie_vpads/c84p10009.html?pos=500&search_params=YTo4OntzOjg6ImluX3N0b2NrIjtpOjA7czoxMjoiY2F0ZWdvcnlfaWRzIjthOjE6e2k6MDtzOjI6Ijg0Ijt9czoxNjoiY2F0ZWdvcnlfcmVjdXJzZSI7YjoxO3M6ODoia2V5d29yZHMiO3M6MDoiIjtzOjk6ImJyYW5kX2lkcyI7TjtzOjQ6Im1vZGUiO3M6MzoiYWxsIjtzOjQ6InNvcnQiO3M6OToicHJpY2VfYXNjIjtzOjEwOiJjb3VudHJ5X2lkIjtzOjE6IjEiO30%3D

Those pads on a clean rim will have a LOT more bite but at the cost of being pretty noisy and poor wet weather performance.

2) Upgrade the pads AND grid the rim. This will have a similar effect as above but will work in all weather conditions. The pads will be a harder compound so have an added bonus of making the brake firmer. https://www.tartybikes.co.uk/vbrake_pads/tnn_engineering_lgv/c84p11243.html?pos=895&search_params=YTo4OntzOjg6ImluX3N0b2NrIjtpOjA7czoxMjoiY2F0ZWdvcnlfaWRzIjthOjE6e2k6MDtzOjI6Ijg0Ijt9czoxNjoiY2F0ZWdvcnlfcmVjdXJzZSI7YjoxO3M6ODoia2V5d29yZHMiO3M6MDoiIjtzOjk6ImJyYW5kX2lkcyI7TjtzOjQ6Im1vZGUiO3M6MzoiYWxsIjtzOjQ6InNvcnQiO3M6OToicHJpY2VfYXNjIjtzOjEwOiJjb3VudHJ5X2lkIjtzOjE6IjEiO30%3D

There is more cost and labour involved as you will have to grind the rim to give a rough texture (video here... 

) but this will give the most reliable bite and overall performance but again will be pretty noisy.

The other things that would help would be a brake booster to stop the arms splaying out and to make sure you have the best cable possible...I recommend the Shimano SP5 outer from Tartybikes with a squoosh of GT85 through it https://www.tartybikes.co.uk/disc_brake_spares/shimano_sp51_outer_cable/c110p11637.html?pos=1600&search_params=YTo4OntzOjg6ImluX3N0b2NrIjtpOjA7czoxMjoiY2F0ZWdvcnlfaWRzIjthOjE6e2k6MDtzOjM6IjU5NyI7fXM6MTY6ImNhdGVnb3J5X3JlY3Vyc2UiO2I6MTtzOjg6ImtleXdvcmRzIjtzOjA6IiI7czo5OiJicmFuZF9pZHMiO047czo0OiJtb2RlIjtzOjM6ImFsbCI7czo0OiJzb3J0IjtzOjk6InByaWNlX2FzYyI7czoxMDoiY291bnRyeV9pZCI7czoxOiIxIjt9

Any or all of those should make a big difference  

[La Bourde]

Hello and welcome,

 

Nice to see another trial addicted guy!

Your setup is quite good:the lever is top and the brake arms good enough. You don't need to change something here.

 

On the xtr lever, you can adjust the pulling ratio. The part holding the cable shall be as close as possible from the pivot. You can adjust this with a screw if I recall correctly.

But consider changing the brakepads for trial specific pads.

The compound is much softer and give much more bite and hold.

It makes a huge difference! You won't have to grind the rim, as long as you ride only when it is dry. Grinding makes the brakes even more powerful, and it is the only way for rim brakes to perform in wet conditions.

Another upgrade can be linear cables/housing like the Odyssey slic cables. They improve the feeling of the brake, the lever feels less spongy. It make a big difference too.

A brake booster can also improve the feeling by increasing the stiffness of the couple frame/brakes. I don't know if this frame is stiff enough, it can be the case though. I prefer to have a slight spongy lever to prevent arm pump. But it is a personal preference maybe.

Another small improvement: shorten the distance where your brakes arm is attached to the cable so that the adjustment dial of the lever is closer to the lever (one or two rotations could be left)

Finally, you can buy better grips. Arm pump is amplified by shocks.

Consider dual density grips.

 

Edit: Ali C. already listed the most important changes

Edited January 18, 2023 by La Bourde

[coldriverjoe]

Thanks @Ali C and @La Bourde! This is exactly the type of information I was looking for. 

I tried to order the jitsie pads from Tarty but unfortunately the international shipping is down at the moment. Would these Discobrakes be similar? https://www.amazon.com/Trials-Specific-Compound-Riding-Length/dp/B00RC38NDE

Replacing and lubricating the cable housing also makes a lot of sense! I will also look at dialing the lever and brake arms. Better grips make sense too.

Much appreciated!

[Mark W]

These should be a pretty similar compound to the pads Ali linked to - Empire are a great shop, so if you're choosing to support Amazon or Empire I know which way I'd go https://www.empirebmx.com/kool-stop-flatland-brake-pads 

Koolstop describe them as "AN EXTREME COMPOUND FOR ONLY EXPERIENCED TRICK OR TRIALS RIDERS needing a compound that WILL INSTANTLY LOCK THE WHEELS." With that level of caps lock usage you know they must be serious... The pad compound will most likely be the same as any of the generic clear pads out there, so on a smooth rim you'll instantly get much better performance.

If you follow the other tips the guys above have given you'll find a night and day difference in how your brake works compared to what it's like now.

The Element is a really capable little bike, by the way! It's an older model compared to what's out now, but they ride really nicely. He's on the 26" version of your bike in this, but here's David Sellero doing some cool stuff way back when: 

The line at 2:18 is so good...

[coldriverjoe]

Thanks @Mark W! I will give the Koolstop pads a try. That's a sweet video .

[coldriverjoe]

17 hours ago, La Bourde said:

On the xtr lever, you can adjust the pulling ratio. The part holding the cable shall be as close as possible from the pivot. You can adjust this with a screw if I recall correctly.

I went down the rabbit hole with this adjustment. Looks like I have the XTR M950 lever with the so-called "servo wave". The cable is pulled by a roller which can move on the slot (shown in picture). In my case, the screw was completely out (servo wave disabled, min leverage). I guess I'm enabling the servo wave by retracting the adjustment screw all the way (shown in the picture). This should give me max leverage for clamping force but I'm wondering if the whole roller business is going to feel weird. Seems like there will be a snappy increase in leverage at some point along the lever travel. Anybody here used a lever like this? 

 

 

Edited January 19, 2023 by coldriverjoe

[La Bourde]

That is the way it should be to obtain the maximal leverage.

I never owned a Xtr lever, but I had LX (with a 3 positions servo wave) and Avid levers (with a similar system). I never had problems.

You will notice that the brake will feel more spongy this way, but this is to expect: applying more force  leads to a higher deformation.

That is why we recommended a better cable or the use of a brake booster.

[Mark W]

7 hours ago, coldriverjoe said:

This should give me max leverage for clamping force but I'm wondering if the whole roller business is going to feel weird. Seems like there will be a snappy increase in leverage at some point along the lever travel. Anybody here used a lever like this? 

On-off power is what you're after, really! The end goal is to use your rear brake as little as possible for manuals, so although it'll have a bit less modulation in that setup compared to if you had it set the other way, you'll get more usable power for trialsy stuff which is where you'll rely on the brake most. As has been said, you'll probably feel a little more of a spongy/mushy feel to the brake but good cables should offset a lot of that. From memory the Element is a reasonably stiff frame but if needs be you could throw a brake booster on there too.

[coldriverjoe]

It all makes sense. Thank you all!

[basstrials]

Hi there,i am a beginner too with pretty much same setup.I got Avid SD 5 arms and Heatsink yellow pads,rim is not grainded.While ago i have used Jitsie(white) v-brakebpads,which is awesome -IMO.I think that they are more suitable for smooth rim compared to Heatsink,i feel them more solid somehow.I am not saying that yellow Hetasink are not good,maybe is that because of the smooth rim.The Jitsie's were quite noisy at the beginning but that stop after while.For the bite,i am not good trials tlrider,i would say that they have more hold than bite,some people says "mushy" or something,maybe that is the right word for.Trying to hope in back wheel,i am 90kgs and they hold well.Give them a try if not going to grind your rim.Take good brake booster,this is must have.Good cable too,like Oddysey one.I would recommend to change the brake lever with Avid Speed Dial 7.

1.Jitsie v brake pads.

2.Oddysey liner cable.

3.Brake booster-good one.

4.Avid Speed Dial 7 lever.

...and make sure,that pads is always perpendicular to the rims,if are noisy you are golden.

P.s. beg you pardon for my english.

All the best.