smokey125 Posted January 30, 2016 Report Share Posted January 30, 2016 Last question about bike changes, I promise! Trying to get my head round the improvement in brakes. Does anyone know what size the pistons in either calliper or master cylinder, front and back on any of the current bikes are? They seem to be unchanged from around 2005 onwards, depending on model. Alternatively has anyone had to service/replace pistons and/or seals in either calliper or master cylinder on any of the current bikes? If so would you be able to tell me the sizes of the various pistons? I’m interested to see what ratio the current brakes run. Quote Link to comment Share on other sites More sharing options...
steve_earle Posted January 30, 2016 Report Share Posted January 30, 2016 Most brakes are the same from around 02 onwards when they changed to 32 spoke wheels with inboard calipers. Front calipers have different designs in the last 5 years but some of the Factory boys still prefer the std Ajp 4 pot, I can't tell the difference. The piston and seal kits are still the same it appears so its basicly 2 piece vs mono block calipers. If you are upgrading the 309, An Ajp 4 pot will bolt straight on and with Galfer pads will make a HUGE difference. On the rear your better off sticking to the Brembo as it's good even though the pads only cover some of the disk! I have some Ajp's kicking around reasonable if you want one. I can have a measure up on some of the calipers I have if you are keen to know the sizes. 1 Quote Link to comment Share on other sites More sharing options...
smokey125 Posted January 31, 2016 Author Report Share Posted January 31, 2016 Thanks for that all very interesting. Steve, I'm not so worried about upgrading the bike, I'm not going to be able to shed enough weight from it to be worthwhile and it would probably be better to start with the discs which were never great from new. Which means I could make it bigger to at least cover the pad fully! Never could understand the idea of the small rear disc! The engineer in me was struggling to understand where the improvement came from. The main advantages of 4 and 6 piston calipers on race bikes don't apply to trials bikes and I was trying to work out where the gain was. Ive looked at the monoblock calipers but had to wonder if a two piece billet caliper would be a better option for a trials bike. I'm also quite surprised that nobody's tried a radial style master cylinder I would of thought that would of offered an improvement over a conventional one! Thanks for the sizes oni nou gives me something to work with. I'm surprised how small the master cylinder pistons are especially for the front! One question about the rear calipers, what pads do they use, is it the same as the older Brembo's? They look the same in the pictures I've found. Quote Link to comment Share on other sites More sharing options...
steve_earle Posted January 31, 2016 Report Share Posted January 31, 2016 The newer rears are different, the Brembos are a larger pad with 2 pins and the newer inboard types have just 1 pin holding them. A 4 pot on the front works well with the standard disk, The heavier the bike the better the brake you need!! Quote Link to comment Share on other sites More sharing options...
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