Brake adaptor mystery

Swissrider

Well-known member
Nov 1, 2018
368
384
Switzerland
When I bought my Rise H30 I had the shop update my front brake to a 203 rotor with STX 4 pot callipers. They had a lot of problems fitting this and had to take an adaptor off another new bike. When I came to change the pads I found that there was a strip about 2mm wide which had not been worn so clearly the calliper was too far away from the disk so the pads were not engaging fully. Checking the Shimano site I noticed that the shop had put the two cone washers between the adaptor and the calliper rather than between the head of the bolt and the calliper. However, when I mounted the callipers correctly the calliper touched the outside of the disk and the wheel would not turn. So, I took it to the shop who were mystified as to what had happened. They told me that the original rotors were 160mm and they made a mistake upgrading to 203 rotor and it should have been a 180mm. I knew this was wrong and didn’t want to lose the advantage of a 203mm rotor so suggested that they fit washers to put the calliper in the correct position. After about an hour and a half they achieved this. However, this seems a bit heath-robinson and my suspicion is that the adaptor is the wrong one. Maybe it is for a 200mm rotor and I need one for a 203mm rotor. I have found Shimano 203mm adaptors on line but I’m not sure which one I need.

  • black/PM 6" to PM +43 mm, in stock
    8.14€

  • black/PM 7" to PM +23 mm, in stock
    11.76€

  • black/PM 8" to PM +3 mm, in stock
    9.95€
    Any advice please
 

Swissrider

Well-known member
Nov 1, 2018
368
384
Switzerland
Thanks for quick reply. What a great forum this is! I just checked my adaptor - it says 40mm instead of 43mm, so that explains the problem. So a bit of a wasted afternoon going to the shop where a bought the bike. The parking cost more than the part I need! No great loss. Actually, despite not being fitted properly, the brake worked very well, better than my sram brakes on my other bike which has a 220mm rotor.
 

Swissrider

Well-known member
Nov 1, 2018
368
384
Switzerland
A quick fix to the problem is to put the washer under the adapter. For both bolts.
Yes, this is what the shop did originally (they used the cup and cone washers that would usually go between the calliper and the head of the screws). This worked but the calliper was too far out so there was an unworn ridge on the pads. Their fix today was to put one cone washers and one thin washer to set the calliper at the correct distance (as you suggest). It is a bit annoying that the shop did not realise that they needed a 43mm adaptor rather than putting on a 40mm adaptor. Once I get hold of the correct adaptor I will sens them some photos of the correct fix!
 

irie

E*POWAH Elite World Champion
Subscriber
May 2, 2022
2,622
2,679
Chichester, W.Sussex, UK
Yes, this is what the shop did originally (they used the cup and cone washers that would usually go between the calliper and the head of the screws). This worked but the calliper was too far out so there was an unworn ridge on the pads. Their fix today was to put one cone washers and one thin washer to set the calliper at the correct distance (as you suggest). It is a bit annoying that the shop did not realise that they needed a 43mm adaptor rather than putting on a 40mm adaptor. Once I get hold of the correct adaptor I will sens them some photos of the correct fix!

If washers are being placed between the adapter and the caliper it would be better to place washers between the fork and the adapter.
 

Swissrider

Well-known member
Nov 1, 2018
368
384
Switzerland
If washers are being placed between the adapter and the caliper it would be better to place washers between the fork and the adapter.
Why? I can move them but I can’t see the difference between moving the adaptor a couple of millimètres out from the fork and moving the caliper a couple of Millimètres out from the adaptor. Don’t both techniques achieve the same result?
 

irie

E*POWAH Elite World Champion
Subscriber
May 2, 2022
2,622
2,679
Chichester, W.Sussex, UK
Why? I can move them but I can’t see the difference between moving the adaptor a couple of millimètres out from the fork and moving the caliper a couple of Millimètres out from the adaptor. Don’t both techniques achieve the same result?

Yes, they achieve the same end result. But assuming that there are two bolts to attach the adapter to the fork and two more bolts to attach the caliper to the adapter then once the adapter with the washers is bolted to the fork then there would be no washers to mess around with when removing and reattaching the caliper to the adapter.
 

Rod B.

Well-known member
Aug 18, 2021
530
924
USA, Orange County Ca.
When I bought my Rise H30 I had the shop update my front brake to a 203 rotor with STX 4 pot callipers. They had a lot of problems fitting this and had to take an adaptor off another new bike. When I came to change the pads I found that there was a strip about 2mm wide which had not been worn so clearly the calliper was too far away from the disk so the pads were not engaging fully. Checking the Shimano site I noticed that the shop had put the two cone washers between the adaptor and the calliper rather than between the head of the bolt and the calliper. However, when I mounted the callipers correctly the calliper touched the outside of the disk and the wheel would not turn. So, I took it to the shop who were mystified as to what had happened. They told me that the original rotors were 160mm and they made a mistake upgrading to 203 rotor and it should have been a 180mm. I knew this was wrong and didn’t want to lose the advantage of a 203mm rotor so suggested that they fit washers to put the calliper in the correct position. After about an hour and a half they achieved this. However, this seems a bit heath-robinson and my suspicion is that the adaptor is the wrong one. Maybe it is for a 200mm rotor and I need one for a 203mm rotor. I have found Shimano 203mm adaptors on line but I’m not sure which one I need.

  • black/PM 6" to PM +43 mm, in stock
    8.14€

  • black/PM 7" to PM +23 mm, in stock
    11.76€

  • black/PM 8" to PM +3 mm, in stock
    9.95€
    Any advice please
Swissrider,

I did a three part series on Shimano brakes, maintenance and Rise brake upgrades. Part # 2 covered brake caliper adapters for the Rise. It includes an adapter chart for the Rise Carbon and Rise Hydro.



 

Swissrider

Well-known member
Nov 1, 2018
368
384
Switzerland
Swissrider,

I did a three part series on Shimano brakes, maintenance and Rise brake upgrades. Part # 2 covered brake caliper adapters for the Rise. It includes an adapter chart for the Rise Carbon and Rise Hydro.



Many thanks for pointing me to your excellent articles. Very thorough and very helpful. Like you, I like to do all my own maintenance both on my bikes and motorbikes. Some of my tools, like my first socket set, I’ve had since I was fifteen. I have seven bikes to maintain (five ebikes) and a motorbike. I spend more time on brakes than anything else; changing pads, dealing with sticky pistons and bleeding them. I think for some owners, brake maintenance can be quite intimidating, with bleeding brakes having a reputation for being a bit of a black art. However, if one persists, one ends up with the “ease of long practice”. This is why articles like yours and the useful videos really help people to overcome any nervousness in dealing with their brakes and, of course, saving a lot of money in the process.
 

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