Agree.
It can be the only reason.
Very tight clearance between front derailleur and rear tyre
Re: Very tight clearance between front derailleur and rear tyre
It can be the only reason.
Mick F. Cornwall
Re: Very tight clearance between front derailleur and rear tyre
Take a look at the bottom bracket cups to see if any spacers have been used. If they are present on the drive side they could be swapped to the non-drive side without causing a problem with chainline.
If this isn’t an option perhaps sourcing a front derailleur clamp with a larger diameter and a crescent shaped shim within it to vary the offset of the mech might work?
Both of these options will rely on the mech having enough free adjustment (in comparison to its position at present) to allow the cage to sit further in.
If this isn’t an option perhaps sourcing a front derailleur clamp with a larger diameter and a crescent shaped shim within it to vary the offset of the mech might work?
Both of these options will rely on the mech having enough free adjustment (in comparison to its position at present) to allow the cage to sit further in.
Last edited by peetee on 23 Jul 2021, 10:07am, edited 1 time in total.
The older I get the more I’m inclined to act my shoe size, not my age.
Re: Very tight clearance between front derailleur and rear tyre
This sounds right to me... can you move the chainline enough so that you don't have to replace anything?
Jonathan
Re: Very tight clearance between front derailleur and rear tyre
Hence my question to the OP asking what the bottom bracket model is (I think a Hollowtech BB is only likely to have spacers if it is an MTB BB). Similarly the reason for my question about the chainset: the OP mentioned that the levers were GRX and if the chainset were also GRX that would have a larger chainline.
The OP has stated that 'the bike was built up with a bit of a mix of components', and the limited/inadequate clearance is most probably due to some component mismatch or incompatibility. Unless the OP provides more information, we are just guessing what the cause might be.
Re: Very tight clearance between front derailleur and rear tyre
The OP states that the FD is Tiagra 4700 (it looks like one too). Also that the Chainset is a Tiagra Compact double. Ok they don't say which edition, but 4550, 4650 and 4750 have all been HT2, so that would be a good guess.
GRX levers and Shimano 11sp/Tiagra 4700 shifters are interchangeable. The kit all seems to be right (with the slightly possible exception that a MTB BB might have been used).
My guess is that the frame is not designed to clear the much longer arm on the newer double FDs Shimano have produced. It swings a lot further inboard when you switch to the big ring than older models used to.
GRX levers and Shimano 11sp/Tiagra 4700 shifters are interchangeable. The kit all seems to be right (with the slightly possible exception that a MTB BB might have been used).
My guess is that the frame is not designed to clear the much longer arm on the newer double FDs Shimano have produced. It swings a lot further inboard when you switch to the big ring than older models used to.
Re: Very tight clearance between front derailleur and rear tyre
It looks to me as if Shimano's braze-on adapter clamp for front derailleurs, SM-AD91, might be designed to position the front derailleur further forward than a generic adapter like the OP has used. Normally generic adapters position the front derailleur roughly in line with the centre of the seat tube. The technical drawings of the SM-AD91 clamp seem to show the derailleur positioned further forwards. Even though it looks like a difference of maybe only a few millimetres, it looks to me as if that might at least partly account for the OP's problem.
From https://si.shimano.com/api/publish/stor ... 08-ENG.pdf,
Re: Very tight clearance between front derailleur and rear tyre
That's a good shout!slowster wrote: ↑23 Jul 2021, 2:24pm It looks to me as if Shimano's braze-on adapter clamp for front derailleurs, SM-AD91, might be designed to position the front derailleur further forward than a generic adapter like the OP has used. Normally generic adapters position the front derailleur roughly in line with the centre of the seat tube. The technical drawings of the SM-AD91 clamp seem to show the derailleur positioned further forwards. Even though it looks like a difference of maybe only a few millimetres, it looks to me as if that might at least partly account for the OP's problem.
My FD is also on a generic mount. rather than a shimano one.
Re: Very tight clearance between front derailleur and rear tyre
You have the wrong frame for that front derailleur.
I should coco.