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disc mount woes

alexm77alexm77 Posts: 23
edited February 2019 in Workshop
I'm guessing I'm not the first person to have made this mistake. I've just bought a Sonder Camino Al frame that's postmount. I've bought shimano 105 R7025/R7070 levers and callipers. As I understand it, the callipers are flatmount, and there's no way to convert them to postmount :cry:

So I guess my options are to send back the brakes, and order just the R7025 levers on their own and find some other compatible post-mount callipers to go with them. Is this correct? If so, is there a Shimano road postmount calliper, or should I just get some SLX calipers?

Rotors are currently 160mm if that makes a difference.

Thanks.

Posts

  • veronese68veronese68 Posts: 24,581 Lives Here
    Correct, you can’t fit flat mount calipers to a post mount frame. Unfortunately for you the other way round is possible, with adaptors post mount calipers can be fitted to a flat mount frame.
    The easiest thing would be to change the brakes for post mount if possible. Alternatively I believe something like SLX calipers will work. But I’d check further rather than just take my word for it. All Shimano calipers use mineral oil so fluid compatibility is fine. You need the same size caliper piston so the amount of movement for lever travel stays the same. Then you just need to be sure hose connections will fit.
  • I'm replacing Sram Rival hydros which I haven't really got on with (not great performance and not very comfortable), so pretty set on moving to Shimano. Got small hands and like the feel of the R7025 levers, so really looking for something that'll work with these.
  • From what I've now read from various internet comments, the levers should work with any of shimano's 2 piston calipers. However, some have a banjo adapter which will make hose fitting harder. Leaning towards getting the deore calipers (BR-M6000) as the hose fitting looks simpler than with SLX. Will there be much performance difference?

    At least the snow means I wasn't riding this weekend anyway :roll:
  • pilot_petepilot_pete Posts: 2,100
    I just updated my winter bike to the new 105 and had to buy post mount callipers to fit the frame. I went Deore M6000 which work fine. I paid £20 each for them, so it’s not exactly bank breaking...

    PP
  • I thought I'd read you can buy adaptors to fit flat mount calipers to post mount frames/forks, but not the other way around.
    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • Nitrous - pretty sure that's not the case. According to this anyway - https://www.bikehugger.com/posts/road-d ... ost-mount/

    There's loads of flatmount fork > postmount caliper adapters about, and Shimano make some. I did find an adapter for the way I need, but it's in Canada, doesn't look common, not guaranteed to fit, so don't think I'll go there.
  • veronese68veronese68 Posts: 24,581 Lives Here
    I thought I'd read you can buy adaptors to fit flat mount calipers to post mount frames/forks, but not the other way around.
    No Alex is right. If you think abot it flat mount sit flat against the frame or fork and post mount are on posts. So if you havea flat mount frame the adaptors replicate the posts and lift the flat mount calipers to the position a post mount would be. To fit flat mount calipers on top of the posts you would have to have some sort of adaptor that fitted the caliper lower than where the post mount sits, can't be done.
  • veronese68veronese68 Posts: 24,581 Lives Here
    Alexm77 wrote:
    From what I've now read from various internet comments, the levers should work with any of shimano's 2 piston calipers. However, some have a banjo adapter which will make hose fitting harder. Leaning towards getting the deore calipers (BR-M6000) as the hose fitting looks simpler than with SLX. Will there be much performance difference?
    That makes sense. Shouldn't think there's much difference in performance if the pistons are the same size and the pads arethe same size. More likely weight and design. Actually you might be better off with the Deore if they have steel pistons and the SLX ceramic as I've heard about ceramic pistons cracking.
  • @Pilot Pete - what hoses did you use? Now got the levers and M6000 calipers and trying to fit SM-BH90s hoses. But the nut supplied with the hoses doesn't fit the lever end - ordered the SS set instead of SSR, which no one seems to stock. Now need to order a couple of flange connector bolts that are about £8 each :shock:

    ...could be a while before this build is finished. Might be able to find a lbs with a couple so I can ride this weekend, but not holding my breath :roll:
  • pilot_petepilot_pete Posts: 2,100
    I just fitted the hoses that were attached to the 105 STIs/ flat mount callipers. Haven’t looked at what their Shimano part number is, but I’m sure a search would throw it up. Did your STIs/ flat mount calipers not come with the hoses?

    Here you go https://productinfo.shimano.com/#/com/3.8?cid=C-453&acid=C-499

    PP
  • The flat mount set came with everything (levers, hoses, calipers), but sent these back to CRC and bought separate levers and M6000 calipers. These didn't come with hoses/bolts unfortunately (though no way to know this from the details on CRC). Would have been better to hold on to the full set and ebayed the flat-mount calipers.

    Just ordered the bolts on ebay, but have yet to see if they actually have them in stock.

    Having spoken to several suppliers now, Madison don't have any and won't get more stock until their next shipment early April. Same goes for the road hoses with the right bolt.

    At least I have a hardtail to keep me pedalling in the mean time 8)

    For anyone else in a similar situation, this thread contains some useful info on compatibility - https://forums.thepaceline.net/showthread.php?t=214639
  • pilot_petepilot_pete Posts: 2,100
    Ahh, I see.

    Yeah, I just took the hoses off the 105 flat mount calipers and they fitted the Deore calipers perfectly. I have the flat mount calipers in their boxes still - can’t be arsed to sell them so I will just keep them as spares (I have 9170 Dura Ace on another bike, so if I get a problem with one of those I at least have a pair of calipers which can keep the bike on the road whilst I decide whether to replace the Dura Ace caliper).

    The difference is I bought a groupset rather than individual components, so returning the calipers wasn’t an option.

    PP
  • jmccabejmccabe Posts: 28
    I know it's late, but here's a link to the Canadian place that makes adapters - https://www.assolutions.ca/. I haven't tried them, but they do a template you can print, then cut out to place against your bike to find out if they'll fit.
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