marin front mech to rear gear coverage problems

supafly1982

Ok guys, might seem a simple straight forward dial in but its not. the Marin came with a tripple and from the day i bought it its never had good gearing. Its got send back to be fixed and camer back "fixed" but was just as bad as when i got it. was looked at by another mechanic but could not sort it fully So i fixed it my self, i had to settle for a comprimise

Front. Rear
Granny ring - 1st to 4th Good no rubbing. 5-9 rubbing
Middle ring - 1st slight rub, 2nd to 7 good. 8 and 9 rubbing
Big ring - 8 and 9 still rubbing

All on front of mech, ive done the usual adjustments. used the L screw to set rear of plate in grany and first. Big ring and 9th set H screw for front of mech gap, but cant get the adjustment to set the gap from front of mech.
I had the gearing i needed for trails so i left it at that.

ive now bought a double SLX bash and again tried to dial it in. i have all the gearing i need in the granny ring, middle ring i still cant get 8th and 9th without it rubbing on the front of mech.
whenever i play with it to sort out 8th and 9th then ive lost the gearing for the granny as chain rubs on rear plate on mech, it just does not seem to have the coverage of all gears, its driving me mad, ive tried moving the angle of mech, using barrel adjuster to tweek it. Ive set the mech L screw so chain is as close as posseble to rear mech plate just to try and ease the chain away from fron plate when using middle ring and 8 & 9th, still no joy

Casette is SRAM, chain is SRAM mech is SLX all original bike componants, SLX double is new, old tripple was SLX

any ideas?

cooldad

viewtopic.php?f=40043&t=12647117

nicklouse

sounds like poor set up or incorrect assuption of what gears are needed.

supafly1982

nicklouse wrote:

sounds like poor set up or incorrect assuption of what gears are needed.

not if you read again what ive wrote, i know what gears i should be using, its just NOT posseble for some reason, i have to admit i was going to wonder who was going to be the first to say incorrect set up.............but as ive tried to explain this is not the case, 2 previous bike mechanics could not sort it, i managed to sort it better for gearing approprate to me. The rear large cog on casette ive been classing as first.

here is a quote from cooldads link

In the smallest front chainring you can use the 3 or 4 LARGEST rear cogs.
In the middle front chainring you can use ALL the rear cogs.
In the largest front chainring you can use the 3 or 4 SMALLEST rear cogs.

and from this i have tried to explain that ive got the granny ring working fine.
middle does not cover all as will not use the 2 smallest cogs
again large ring when i had the tripple would not use the 2 smallest :shock:

I usually do what the Park Tools site tells you, the link that Nick gets people to read, i normally dont have problems doing it this way but the Marin just does not seem to dial in.

With the double and bash i cant get the 2 smallest ( 8 & 9 ) gears in use without chain rubbing off front plate on front mech.
I have done all the normal set up proceedures and it does not work, nothing works, the adjustmet to increase the gap between front mech front plate will not work, it will lessen the gap but the chain is all ready against the plate so obviously im not lessening the gap.

i fail to see how set up is wrong when following the correct proceedure that has worked on all the other bikes. Just saying its "set up wrong" is not much help :? its been done to the best of my knowledge according to your advice.
and how can it be incorrect assumption of what gears are needed, i know what gears are to be used within what range and what ones not to use. If you read again you will see what im trying to explain is well within all these ranges.

cooldad

You have changed the cranks is the spacing correct? Is the chainline out?
Could be incorrect spacer(s).

supafly1982

cooldad wrote:

You have changed the cranks is the spacing correct? Is the chainline out?
Could be incorrect spacer(s).

both SLX and has the correct spacing according to its guide :? its a puzzle

Chunkers1980

It may still be SLX but is different.

I'd double check the height and angle on your mech. Needs to be pretty much perfect.

supafly1982

Chunkers1980 wrote:

It may still be SLX but is different.

I'd double check the height and angle on your mech. Needs to be pretty much perfect.

what would you say is the correct height when using a bash? in your oppinion.

I have tried various angles too as the norm didnt work. again i will try to explain what appears to be te problem. it is, as if the front mech is not wide enough to cover all angles, specifficly the gearing on the 2 rear small cogs when all the other gears are fine, if you adjust the mech to run free and clear in these gears then in the granny ring and the large rear gears the chain rubs off of the rear plate on front mech, the exact opposite to original problem.

delcol

have you got a bent chain ring or cog on the cassette..

my scott road bike was doing this in top gear the large chain ring was bent or more warped..

would a bent mech hanger effect chainline ?

1mancity2

supafly1982 wrote:

Chunkers1980 wrote:

It may still be SLX but is different.

I'd double check the height and angle on your mech. Needs to be pretty much perfect.

what would you say is the correct height when using a bash? in your oppinion.

I have tried various angles too as the norm didnt work. again i will try to explain what appears to be te problem. it is, as if the front mech is not wide enough to cover all angles, specifficly the gearing on the 2 rear small cogs when all the other gears are fine, if you adjust the mech to run free and clear in these gears then in the granny ring and the large rear gears the chain rubs off of the rear plate on front mech, the exact opposite to original problem.

Mine is set 2mm over the bash guard

1mancity2

Just a thought, is your rear mech clean and lubed?

Mine won't shift properly when dirty and causes the chain to drag and rub.

supafly1982

1mancity2 wrote:

Just a thought, is your rear mech clean and lubed?

Mine won't shift properly when dirty and causes the chain to drag and rub.

aye its not over the bash, but i cant get the mech to shift right over so when you shift up to big cog its clear of chain, the adjust screw just wont make it move and you cant use the barrel adjuster as that moves the whole mech and i'll loose the granny ring indexing, they should stick these in crackers, beats any little crappy plastic puzzle

cooldad

I don't understand - you say the mech won't move far enough to clear the big ring, which now that you have 2 on the front is effectively the middle ring?
As a matter of interest what size is the BB shell, and where are the spacers?

supafly1982

i have a saint 2 spd shifter for the double and bash, all is exactly as ive said. I will measure it and tell you when i get a chance tomorrow, think its 73mm

Chunkers1980

supafly1982 wrote:

i have a saint 2 spd shifter for the double and bash, all is exactly as ive said. I will measure it and tell you when i get a chance tomorrow, think its 73mm

I take it you still have the 3 spd mech? and shifter from your old setup?

Try that and see, one at a time might be best - you'll rule a few things out.

nicklouse

Right please lst all the parts you have. ( part numbers as well)

Where has this Saint shifter come from? It was not mentioned in the first post.

Still sounds like poor set up or you have just bought parts tht don't work together.

barty81

ive got the same problem with my front mech! i have chain rub when the chain is on the big up front and little on back, even with the h limit screw at its outmost.dont quote me on this!! but can you fine tune the cage by increasing the cable tension via the shifter barrell? this will move the cage out that bit more to give that 2mm gap between outer edge of the cage and chain.havent tried it as of yet! am i correct in thinking this or am i talking s**t? :oops:

cooldad

No it won't work because if the h screw is at the limit, the mech can't move any further no matter how much cable you try and pull.
If there is rub in any reasonable ratios, it's either component mismatch or bad setup. If the bits are right and set up correctly, they work.
Millions can't be wrong.

supafly1982

barty81 wrote:

ive got the same problem with my front mech! i have chain rub when the chain is on the big up front and little on back, even with the h limit screw at its outmost.dont quote me on this!! but can you fine tune the cage by increasing the cable tension via the shifter barrell? this will move the cage out that bit more to give that 2mm gap between outer edge of the cage and chain.havent tried it as of yet! am i correct in thinking this or am i talking s**t? :oops:

if i do that i will loose the indexing for the granny ring as it will move the problem from outer ring and front of mech rub to rear rinngs and rear of front mech chain rub.

nicklouse wrote:

Right please lst all the parts you have. ( part numbers as well)

Where has this Saint shifter come from? It was not mentioned in the first post.

Still sounds like poor set up or you have just bought parts tht don't work together.

ok, original parts are the casette, chain and slx front mech, the gears never worked propperly from the start. this includes XT rear mech and SLX 3 spd shifter Sl M660 which was coupled with the slx tripple, these componants are going on the HT build.

componants original and new which are on the Marin just now are:

Sram chain PG-951
Sram casette PG- 970
SLX front mech FD M660
SLX double and bash FC M665
Saint 2 spd shifter SL M810
Saint rear mech FD M810 A

Now the double bash, slx front mech was the same with the XT rear mech and SLX shifters with the same results so its cant be a the mech or shifters thats the problem, again the double has same problem with the tripple and the front mech is the same on all set ups too.

the BB shell is 68mm with 2 spacers drive side and one none drive side.

I originaly bought a saint front mech but they are 83mm BB shell compatable only, i was after the wide mech cage on it as i hoped this would solve the issue but cant use them for reason just mentioned.

supafly1982

cooldad wrote:

No it won't work because if the h screw is at the limit, the mech can't move any further no matter how much cable you try and pull.
If there is rub in any reasonable ratios, it's either component mismatch or bad setup. If the bits are right and set up correctly, they work.
Millions can't be wrong.

see thats what i keep thinking, the parts are built to do a job, you set them all up correctly and they will do the job, set up badly and they wont.....but i cant see where ive gone wrong :roll: im just going round in circles, no doubt it will be somethig stupidly simple

supafly1982

nicklouse wrote:

Right please lst all the parts you have. ( part numbers as well)

Where has this Saint shifter come from? It was not mentioned in the first post.

Still sounds like poor set up or you have just bought parts tht don't work together.

Sram chain PG-951
Sram casette PG- 970
SLX front mech FD M660
SLX double and bash FC M665
Saint 2 spd shifter SL M810
Saint rear mech FD M810 A

supafly1982

faulty front mech? its never worked from new, might swap it over and see what the crack is.

On the plus side i took the bike out tonight, all gearing is super crisp and instant, only the rubbing to sort, its actually the 3 smallest but just as 7th is only lightly touching but when you give it some it rubs badly. apart from that i was impressed with the smoothness of the changes and the new ratios im using, will need all gears though, hopefully trying out this new mech will solve the issue

supafly1982

well i changed front mech to another SLX mech, diald it in, problem solved, looks like it was a faulty mech all this time, not as thick as you think happy days, its been a pain in the arse since ive had the bike