Belt drive Mercedes MTB gear slipping

bobg

Über Member
A frind of mine in my LBS asked me to have a quick look at bike with slipping gears cos he was busy! Little did I realise....

It has an SRAM Inter 7 hub and what seems to be a very odd variomaric gear change... cant really describe it except that its horrible to ride, noisy and the gears slip. Before I start tinkering, has anybody out there got any experience of these SRAM enclosed gear hubs. I can see the usual cable adjuster but thats about all...
ta
 
Location
EDINBURGH
I think there are service diagrams available on the sram site. Ignore the belt drive, the hub is the same for belt or chain.
 

MartinC

Über Member
Location
Cheltenham
SRAM make a 7 speed internal hub gear (often known as a SRAM Spectro). An Inter 7 is a 7 speed Shimano Nexus hub gear. They have very different gear change arrangements. If a hub gear is noisy and slips it normally means that the gear change is out of adjustment and should be corrected promptly to avoid damage to the hub internals.

For both hubs adustment is by using a cable adjuster to align marks on the change mechanism - but the detail depends on which hub it is. Both SRAM and Shimano have documentation online that covers this.
 
OP
bobg

bobg

Über Member
Thanks chaps. I found the instructions and did exactly what it said but I fear that there's something terminal going on inside because it's clunking and grinding even more. Good job it wasnt mine, they're hugely expensive. I cant stress how horrible the bike was. I wonder why Mercedes produced it. The roller that bears against the middle of the tyre to operate the belt drive needs considerable pressure so its a pig to push plus I could hardly lift it onto the stand. Anway it back with the LBS now..
 
OP
bobg

bobg

Über Member
biggs682 said:
have seen a few of these go for stupid money ie loads on e bay and often thought about having a dabble
After today I think I'd give them a miss. However, they're very popular on Moultons. I like the external simplicity in the same way as I still use old Sturmey Archer on some of my 50's bikes. Having removed the rear wheel and staggered across the garage with the weight I'm somewhat put off. Mind you the silly belt drive and effort needed to turn the pedals coloured my view
 

hubgearfreak

Über Member
bobg said:
Thanks chaps. I found the instructions and did exactly what it said but I fear that there's something terminal going on inside because it's clunking and grinding even more.
is it sram or shimano?
 

biggs682

Smile a mile bike provider
Location
Northamptonshire
hopefully have managed to track a belt driven Merecedes touring bike down at a decent price so hopefully will be riding a merc next week , pics to follow
 
.... The roller that bears against the middle of the tyre to operate the belt drive ..
Eh?
 

biggs682

Smile a mile bike provider
Location
Northamptonshire
just picked up after short test ride . 7 speed nexus hub geared , drum brakes fr & rr that are very good , adjustable load dynamo lighting , belt driven , butterfly bars , built in rear carrier that doubles up as a d lock ! alloy frame so quite light .

cant wait to give it some air in the tyres and a bit more distance to see how it truely rides .
 

biggs682

Smile a mile bike provider
Location
Northamptonshire
ok have just come back from first ride round block between jobs , very smooth to ride almost feels like when in wrong gear you can feel the notches in the belt as you pedal , but so far so good .

sorry about the pics its just the sun to bright and the shady part of garden full of washing line etc etc
merc.jpg
 

CamilloBenzo

New Member
[...] The roller that bears against the middle of the tyre to operate the belt drive needs considerable pressure so its a pig to push plus I could hardly lift it onto the stand. [...]
That's the dynamo... 🤦‍♂️

Is it some kind of torque sensing auto tranny or what?
Just a simple dynamo.
No idea what led OP to thinking it was somehow magically controlling the belt.

Cheers.
 
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