Question to bike 6.8 plus with Bosch motor

[eia]

Hello
I bought a Focus jam2 plus Version with Bosch gen 4 for my wife. Actually I wanted to have the nine version but it was out of stock. Is the fox 34 fork of the plus Version compatible with 29 wheels?

And if you later change the rear wheel to 27,5. How about the Bosch Motor? Do you have to modify the Software because of different tuning speed?

 

[Richt20000]

Hello
I bought a Focus jam2 plus Version with Bosch gen 4 for my wife. Actually I wanted to have the nine version but it was out of stock. Is the fox 34 fork of the plus Version compatible with 29 wheels?

And if you later change the rear wheel to 27,5. How about the Bosch Motor? Do you have to modify the Software because of different tuning speed?

Yes, you can put 29 wheels straight in.
If the flip chip is in the lower/shorter position then you’ll need to swap that around and put in a longer chain.

Don’t need to touch the motor, it just means the cut off will be maybe 1mph higher if they have configured wheelsize for plus tires and you put 29ers in there.

 

[Gee tomac]

Very lucky wife ?

 

[Sijmes]

Yes, you can put 29 wheels straight in.
If the flip chip is in the lower/shorter position then you’ll need to swap that around and put in a longer chain.

Don’t need to touch the motor, it just means the cut off will be maybe 1mph higher if they have configured wheelsize for plus tires and you put 29ers in there.

Isnt there asomething about chain length too ?

 

[Richt20000]

Isnt there asomething about chain length too ?

Yes, if you read my post again, you’ll see I mention you’ll need a longer chain ;-)

 

[Sijmes]

Yes, if you read my post again, you’ll see I mention you’ll need a longer chain ;-)

Sorry, Ill read through before chipping in next time ;-) Got chain on the brain, I think mines eaten one already after 900km. Do we know how mant links we are supposed to have ?

 

[Richt20000]

Sorry, Ill read through before chipping in next time ;-) Got chain on the brain, I think mines eaten one already after 900km. Do we know how mant links we are supposed to have ?

When I changed from 29 to 27.5 I think I needed to take 4 Links out but I can’t remeber. Best way is to measure again from scratch.

 

[Sijmes]

When I changed from 29 to 27.5 I think I needed to take 4 Links out but I can’t remeber. Best way is to measure again from scratch.

That would be chain over largest sprocket and not through derailleur, but then how many links extra ?

 

[Richt20000]

That would be chain over largest sprocket and not through derailleur, but then how many links extra ?

I usualy do 2 links, so 3 rivits.
You do this with the air out of the shock and the bike pushed down into fully compressed, so shock is bottomed out.

 

[GrahamPaul]

That would be chain over largest sprocket and not through derailleur, but then how many links extra ?

If you are using a Shimano drivetrain, go to this link and type your derailleur model into the search field. In the listing look for the dealer manual (DM) and this will tell you all you need to know for setting up the correct length of chain.

 

[Sijmes]

I usualy do 2 links, so 3 rivits.
You do this with the air out of the shock and the bike pushed down into fully compressed, so shock is bottomed out.

Good rule of thumb method, thanks, see how it compares to the link no in the comment here beneath.

 

[Sijmes]

If you are using a Shimano drivetrain, go to this link and type your derailleur model into the search field. In the listing look for the dealer manual (DM) and this will tell you all you need to know for setting up the correct length of chain.

Great stuff, will check tonight, new chain in the post ??

 

[GrahamPaul]

Great stuff, will check tonight, new chain in the post ??

Just a thought, if it's a 1x12 setup, then type in your chain type and cassette type into the Shimano site. From memory, you need either 5 or 6 links, not two. That's why it's important to check the dealer's manual.

 

[Richt20000]

Just a thought, if it's a 1x12 setup, then type in your chain type and cassette type into the Shimano site. From memory, you need either 5 or 6 links, not two. That's why it's important to check the dealer's manual.

5-6 will be for non-compressed shock surely?

Well I’ve never had a problem with 2 and if it was 3-4 too short it would have ripped off my mech by now.

 

[steve_sordy]

I can think of six ways of determining the correct chain length, but I missed a word out last time I posted it and got a bit of a wigging!

 

[GrahamPaul]

5-6 will be for non-compressed shock surely?

Well I’ve never had a problem with 2 and if it was 3-4 too short it would have ripped off my mech by now.

I'm just quoting the manufacturer's guidelines to you. It's up to you whether you want to do your own thing - but it will be harder to argue with Shimano that their products are not giving you good mileage if you don't follow their recommendations. Extract for the M7100 derailleur:

 

[GrahamPaul]

I can think of six ways of determining the correct chain length, but I missed a word out last time I posted it and got a bit of a wigging!

Yabbut.... the word was "not"...

 

[Richt20000]

Yep, that diagram says ‘without any load to the suspension’

 

[Sijmes]

Im still waiting for my chain to arrive :-(

 

[Sijmes]

The link to the Shimano site, like the diagram here above, said five to 6 links. This I tried and when the bike was in 12th gear, the derailleur was redundant and the chain was hanging on the chainstay. Taking another 2 links out fixed this, adding a little tension to the drive train. I still have to test it off-road though.

 

[GrahamPaul]

The link to the Shimano site, like the diagram here above, said five to 6 links. This I tried and when the bike was in 12th gear, the derailleur was redundant and the chain was hanging on the chainstay. Taking another 2 links out fixed this, adding a little tension to the drive train. I still have to test it off-road though.

Not wanting to teach you how to suck eggs, but two questions which might help others who are reading this thread:

1) Did you just look at the chain hanging there without sitting on the saddle? The slack on mine gets taken up as soon as there's some sag on the suspension.
2) Did you put the chain onto the biggest ring and then release the air from your rear suspension to check that your derailleur can cope with the full movement of your suspension?

If you didn't do either of these things, I suggest you have a quick check to save your rear mech getting torn off unexpectedly.

 

[Sijmes]

Hi Graham, I appreciate your concern. Shimanos instructions were to be followed without load to the suspension and five to six links. Six in my case. At this length, leaving the ground in top gear and possibly the gears below, would allow the chain to scrape over part of the now unsprung derailleur, that it should never come into contact with, and also my chainstay. I have let all the air out of my suspension and although the derailleur is extended pretty far, it isn't to the max and by pressing further with my fingers it allows for yet a little more chain play. This is the most extreme position I assume, which probably won't happen that often. Shimano follow up later with basically the same thing that you say, however this sentence isn't in the "chain length" section but shortly after.

 

[GrahamPaul]

Hi Graham, I appreciate your concern. Shimanos instructions were to be followed without load to the suspension and five to six links. Six in my case. At this length, leaving the ground in top gear and possibly the gears below, would allow the chain to scrape over part of the now unsprung derailleur, that it should never come into contact with, and also my chainstay. I have let all the air out of my suspension and although the derailleur is extended pretty far, it isn't to the max and by pressing further with my fingers it allows for yet a little more chain play. This is the most extreme position I assume, which probably won't happen that often. Shimano follow up later with basically the same thing that you say, however this sentence isn't in the "chain length" section but shortly after.

Yup. You've pretty much covered it. As long as there's still some movement in that derailleur, you should be okay. Always hard to tell from a photo. Perhaps @Gary can cast his professional eye over it?

 

[Sijmes]

It's at quite an angle but I doubt I'll ever bottom out in 1st gear unless I go out with MacAskill for an afternoon ?

 

[Gary]

Yup. You've pretty much covered it. As long as there's still some movement in that derailleur, you should be okay. Always hard to tell from a photo. Perhaps @Gary can cast his professional eye over it?

no time to read the full thread just now, but if the shock is fully bottomed out in the pic above (and full bottom out is the point of greatest chain growth) and the mech cage still has a little room to pivot upwards then your chain is at it's very shortest length you can safely run. Runnin gthe chain this short will also mean stronger chain tension (and retention) and less chain slap when in the smallest sprockets.
Do bear in mind, altering your B-tension screw now to increase top jockey clearance will reduce the amount of leway you've allowed for in the mech cage.
But yes. it's extremely unlikely you'll ever fully bottom out any bike in its very lowest gear. Except for maybe a DH bike running a 5 speed close ratio cassette.

 

[Sijmes]

no time to read the full thread just now, but if the shock is fully bottomed out in the pic above (and full bottom out is the point of greatest chain growth) and the mech cage still has a little room to pivot upwards then your chain is at it's very shortest length you can safely run. Runnin gthe chain this short will also mean stronger chain tension (and retention) and less chain slap when in the smallest sprockets.
Do bear in mind, altering your B-tension screw now to increase top jockey clearance will reduce the amount of leway you've allowed for in the mech cage.
But yes. it's extremely unlikely you'll ever fully bottom out any bike in its very lowest gear. Except for maybe a DH bike running a 5 speed close ratio cassette.

Thanks for checking Gary. Well there's one thing we can be sure of, this chain is only going to get longer ???