Hi,

I’m finally building up my hardtail. The help I need is this problem I have fitting these old HOPE M4 brakes that bought from a mate of mine. The front rotor seems to be only half way into the caliper and the rear rotor is too far in the caliper, causing the rotor to touch the back end of the caliper. Both rotors are 180mm and I have the 20mm + adaptors.

Im not too sure if a 183mm front rotor will solve the front problem and a 40mm + adaptor will solve the back problem. The mate I bought the off said he ran them with the same setup on a old Marin hardtail and also a yeti 575. Both with no problems.

Any info on this will be very helpfully.

Cheers

Gaz

how old are the brakes? Post mount or IS mount? ( if IS what number caliper) mono or pre mono? Is or post mount fork ( assuming IS mount frame.

Use washers to fine tune the positioning for the rear. What rotors are they? Proper Hope?

Are the mounts the right way round?

The pre mono M4s used disc sizes 165/185/205.
Whats the caliper number?

TandemJeremy – Member
Are the mounts the right way round?

Ha ha ha ha who would be that silly to do that? 😳 😳

Remove calipers from hoses
Swap calipers over
do it all up again 🙂

I.S. mounts on the frame/forks are a different distance from the axle front to rear, ie the hope number 5 (i think) caliper needs a 180mm rotor on front and 160 on the back.
If you have rotors the same size then you will have one caliper number 3 and one caliper number 5 (or something like that – check inside the mounting legs and the number is usually machined in there.

Nick

[/quote]The pre mono M4s used disc sizes 165/185/205.
Whats the caliper number?

My old mono m4s are 200/180, new are 203/183 I think. Hope have a chart on the website to work out what adaptors to use but i can’t get it to work on my phone. Give the guys a call and they’ll sort you out. It’s one of the reasons lots of people buy their kit.

I’ve already checked they are the right way round. I don’t know what model they are ie mono or pre mono and don’t know the caliper numbers either. But I will check when I get home tonight after work.

The rear is a IS to IS and the front is POST to IS.

Both calipers are No’3

This may be not be a help, but I have 165mm disc XTRs on my Trans-AM, I can always take a photo of it for you to compare?

Mail me if you feel it will be of assistance.

rear no 3 caliper is a 160 mm disc I think without an adaptor so with a plus 20 its a 180 mmm disc

front no 3 is a 180 disc on a IS mount fork Does the pm to IS adaptor add 20MM? dunno

so _ I am abit baffled waht is going on

Phil_H – Member

The pre mono M4s used disc sizes 165/185/205.
Whats the caliper number?

this might be right (and then might be the answer) but I thought mine were 180 and 200 on the tandem. which had old m4s but mine apper to be number 8 calipers

Split calliper m4 brakes with the mini lever with the number 3 calliper half were 185 front and 165 rear. The front post to IS adaptor will also add 20 mm to that.

so thats on IS mounts on the frame / forks? so the OP needs a 165 rear disc and no adaptor or a 185 and a + 20 adaptor and a 205 front disc with the pm to IS adaptor?

so i now know that i need a 205mm front disc. but the back should be ok really. i had a closer look before and because it seems to be only touch the rear end of the caliper. the transition transAM frame has rear drop outs for a singlespeed. so to make it work with a rear mech i am supplied with insert caps for the drop outs, but they seem to push the wheel off center of the caliper with disc.

You need a 165 on the rear. You said you have a 180. That means the calliper is sitting 7.5 mm too low. The angle of the tabs might make it look like It’s only out at one end but from what you say, the rotor is the wrong size.

so a 165 rotor without the adaptor

On the rear, a 165 and number 3 calliper will bolt IS to IS. I’m not familiar with your frame but it shouldn’t do anything odd.

thanx i’ll let u know how i get on. 😀