To all rear disc boyz: 32h or 36h rim? Hope mono m4 or mono trial?

[Chris]

I'm planing to switch to a disc on the rear and I was wondering which rim I should go for. Standard 32 hole rim or 36? Does it make much of a difference having 4 more spokes? I don't know how much it would increase the stiffness of the wheel.

If 36 is the better choice, I'd get a tryall 47mm, as the new ECHO rims are not available with 36 holes...

btw, what do you think about this disc tap, compared to others you've seen? It's on the MBK T1000 frame.

http://82.110.105.16/tartybikes.co.uk/images/large_mbkdisc.jpg

And which disc would you go for? I'd say the hope mono trial 180mm is fine. But what about the Hope mono m4? It has a four piston caliper, whereas the trial has only 2. But from the looks the pistons on the mono trial seem to be bigger, meaning more power?

http://www.hopegb.com/photos/mtrG.jpg
http://www.hopegb.com/photos/mm4rbG.jpg

The only negative thing about the mono trial is that it's limited to a 180mm rotor. The mono m4 also comes with a 200mm caliper.
So which one is stronger?

Mono m4: 4 pistons + 200mm rotor or
mono trial: 2 larger (?) pistons + 180mm rotor?

[tomacropod]

is this for your downhill bike? Because the downhill brake should be on your downhill bike, the trials brake on your trials bike. Dead simple eh?

- Joel

[Chris]

uhm awesome reply :D I mean I'm just asking... maybe the mono m4 is stronger due to it having more pistons... Actually I considerd the mono m4 because of the option to run a larger disc. 200mm instead of a 180mm.

I just cross post from TF... to get more opinions on that.

I just had a look at tartybikes. The 180mm mono trial caliper is the same for front and rear? The MBK frame features a +20mm mount, so I can take the 180mm caliper and run a 200mm rotor? That would be awesome and I guess it would be better than the mono m4 with a 200mm rotor.

http://82.110.105.16/tartybikes.co.uk/images/large_trialcaliper3.jpg

[RomanC]

I am running a 36spoke wheel with tightly sprung spokes. Unlike other dual disc bikes I tried there is very little play in the wheel. Say, when you do a pedal kick and lock the rear in the air you will feel the hub stop but the wheel will still continue. It creates a feeling of a spongy wheel. As far as brakes go I won't comment as I am just rocking a 185 Avid

[carnagr]

The 4 pistons on the M4 allow for more modulation. On a trials bike - especially the back end of one - you don't REALLY need modulation, and the one bigger piston of the Mono Trials will definitely give you more power. Hope this helped.

[Chris]

yea, I think I'll get a mono trial and a tryall 36h rim. I hope I can finally sell my xtp frame.. then I can order the MBK :)

[smudge]

If you're set on choosing between the M4 and the MTrials, pick the MTrials. The number of pistons in a brake have nothing to do with power. The surface area ratio between the master piston and the slave piston make the difference (with rotor radius remaining constant). Hope's entire line of brakes EXCLUDING THE MTRIALS have the exact same ratio. Each brake has different heat dissipation properties which makes the M6 and M4 better suited to DH and FR type usage.

The MTrials definitely has more power due to the larger caliper piston surface area, but will also overheat much more quickly than any other brake in the Hope line and thus shouldn't be used for anything other than trials.

[ChrisB]

just get the mono trials and be done with it.

[flixlee]

I currently run two dual disc stock bikes, one with Hope M Trials/ Try-All and the other with Mono M4. The MTrials definatly has a larger slave cylinder area and therefore should be more powerful. However, this also means the lever has a slightly "mushy" feel to it, especially when compared to the mono M4. Personally, I prefer the M4 in the back (180mm rotor) over the MTrials. Lock up is very secure and inspires confidence even when wet. Actually better when wet.
As to 36 or 32 hole? A good wheel build on a 32 hole will feel just fine.
Just my two cents.