The Ugly American Posted August 3 Report Share Posted August 3 I'm retrofitting a retro bike with some newer style parts because finding certain standards like 32 hole 40mm rim brake compatible rims seems nearly impossible these days (for example), and I'd like to be able to just re-order parts as needed without the scavenger hunt. I hit up Tarty for some clean rims on sale and nearly got hung up with the offset spokes on the disc caliper. I got away with that by a couple of millimeters on a non-trials fork. But this old planet ex- isn't keen on allowing a 47mm rim in between these HS33's without some modifications. The good news is I'm getting an extra set of pads out of every set of pads because I'll need to cut half of those off and just re-glue them when I wear through the first part. The mod I'm hesitant to do though I'm certain it will be fine, is shorting the pad guide posts on the pistons by about 4mm on each side. Has anyone else ever done this? And did you ever had an issue with it if you ended up swapping the brake to a different frame afterward? I've also considered modifying another brake booster I have to see if I can go about it that way, but I have to put the v-brake adapter mounts at a pretty extreme angle to go about it that way, putting the hoses in jeopardy from heel strikes, and they'll still barely clear doing it. Any advice would be great. Thank you. Quote Link to comment Share on other sites More sharing options...
Alex Dark Posted August 3 Report Share Posted August 3 Shortening the pad prongs was something that was done quite a lot back in the day, I don’t remember any people having much problem with it. Might be an issue if you swap to a frame with a lot wider spaced mounts. 1 Quote Link to comment Share on other sites More sharing options...
La Bourde Posted August 3 Report Share Posted August 3 The old Magura Evo mounting hardware was asymmetric, so that the offset of the callipers could be increased for wider rims. Here in the narrow rim configuration: 1 Quote Link to comment Share on other sites More sharing options...
La Bourde Posted August 3 Report Share Posted August 3 (edited) But if the callipers are even further, then you might have an issue with the cranks. So you will need a 128mm wide bottom bracket at least. Regarding the brake booster: the original one from magura does not fit most trial frame. That is the main reason why I prefer a V-brake setup on a frame with v-brake bosses: deore calliper, avid lever, shimano sp41 hose, jitsie pads or bmx pads from odyssey and you have an amazing combo. Edited August 3 by La Bourde 2 Quote Link to comment Share on other sites More sharing options...
The Ugly American Posted August 5 Author Report Share Posted August 5 On 8/3/2024 at 4:17 AM, La Bourde said: The old Magura Evo mounting hardware was asymmetric, so that the offset of the callipers could be increased for wider rims. On 8/3/2024 at 4:19 AM, La Bourde said: But if the callipers are even further, then you might have an issue with the cranks. So you will need a 128mm wide bottom bracket at least. Regarding the brake booster: the original one from magura does not fit most trial frame. That is the main reason why I prefer a V-brake setup on a frame with v-brake bosses: deore calliper, avid lever, shimano sp41 hose, jitsie pads or bmx pads from odyssey and you have an amazing combo. I have XT v-brakes as a backup, and I always had great experiences with regular old Koolstops with those. I thought something looked off about these new mounts, this is the first time I've ever run Magura's with the adapter. When this frame was made I was just using regular cross-country frames and stuck with v-brakes. I remember always wanting a Planet-X, but never being able to get one. By the time I started buying actual trials bikes, they didn't have seats anymore and BBs were over plus 30. I found some asymmetrical adapters and pieces on eBay but because "retro" they want as much as I paid for the brake for em. I'd rather machine 5mm off the ones I have and call it a day. I hate modifying brand-new parts but that's what happens when you try and set up a frame older than Charlie Rolls with brakes from 2024. Quote Link to comment Share on other sites More sharing options...
The Ugly American Posted August 5 Author Report Share Posted August 5 On 8/3/2024 at 3:38 AM, Alex Dark said: Shortening the pad prongs was something that was done quite a lot back in the day, I don’t remember any people having much problem with it. Might be an issue if you swap to a frame with a lot wider spaced mounts. Quote Link to comment Share on other sites More sharing options...
The Ugly American Posted August 6 Author Report Share Posted August 6 Well... I got the rear hub in the mail today so I laced up the back wheel. Before I bother fitting this brake set up to this rim... have either of you ever had problems with Clean rims? I can see daylight through the seem. It's not confidence-inspiring. Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted August 6 Report Share Posted August 6 Yep completely fine / normal. 1 Quote Link to comment Share on other sites More sharing options...
cwtrials Posted August 6 Report Share Posted August 6 Yup. Most rims are pinned, not welded, so that is completely normal. 1 Quote Link to comment Share on other sites More sharing options...
The Ugly American Posted August 6 Author Report Share Posted August 6 3 hours ago, AdamR28 said: Yep completely fine / normal. 2 minutes ago, cwtrials said: Yup. Most rims are pinned, not welded, so that is completely normal. That's wild... I've laced a lot of rims and I've only ever seen a gap like that after I've banged the crap out of them. Although it's been a while since I've touched a single wall rim. Here's hoping it doesn't buckle under 220lbs of fat old guy. 😂 Quote Link to comment Share on other sites More sharing options...
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