Bicycle gear hub - not smooth in 3rd and 4th

Johnmcl7

On a thread about commuting and cycling there were a couple of responses about gear hubs so I thought I'd ask for advice from anyone who has experience with them. I have an eight speed Nexus rear hub with rollerbrake which is the standard version rather than the better red line model and the problem is while it is very smooth in some gears (mainly 5th and 6th) it's quite rough in others, mainly 3rd and 4th. I still get drive ok in 3rd and 4th but there's an audible grinding noise and I can feel vibration through the pedals which doesn't sound right. It's been like this since I bought it so I took it back to the bike shop who shipped the rear hub back to Shimano and it came back around a month later absolutely identical to how it was before. As I'd been without the bike for a month I decided to stick with it partially because I needed the and partially because I thought if the problem became worse it would hopefully be more likely to get fixed.

The bike is approaching the end of its one year warranty so I'm thinking of putting the bike back in for repair and see if anything gets done. The hub is still the same as it was and while it does function I generally avoid third and fourth gear and feel if I don't try getting it fixed again, I will regret it. Unusually I don't need the bike for the next few weeks but I do need it in a month for a charity cycle although worst comes to the worst I could hire a bike.

The flip side is that on reading around I notice quite a few people mentioning gears being grindy on this hub so I'm wondering if it's just something I have to live with or look at upgrading the hub. From what I can gather the better Alfine hubs are not compatible because they use a disc brake which I don't have the mountings for which leaves the Nexus-8 red line hub which is apparently an Alfine-8 with the rollerbrake instead of disc brake and meant to be smoother and better sealed than the standard Nexus unit. The problem is I can hardly find anywhere with this part for sale and I don't know what the best way to go about getting a wheel onto it is? I also don't know how standard the parts are, my bike has a carbon belt drive rather than a chain so it obviously uses a different sprocket.

Thanks for any thoughts,
John

Norman_Castle

It's been like this since I bought it so I took it back to the bike shop who shipped the rear hub back to Shimano and it came back around a month later absolutely identical to how it was before.

Does the bike shop have an opinion on the hub and do they have bikes with similar hubs for you to try. If so you could identify if your problem is normal for this hub.

Johnmcl7

No, they didn't really have an opinion on it themselves at the time but they admitted they have very little experience with gear hubs which they were completely open about. As they're an authorised Trek outlet (you can't mail order Trek bikes) and the carbon belt drive was knew to me I ordered through them but they're a small shop and mainly have mountain bikes as it's not a big place I live in so commuting bikes aren't that popular. I doubt they have any carbon belt drives bikes in stock particularly as Trek seemed to have stopped producing them.

The shop have been helpful in the past so will probably phone them anyway and see what they think.

John

Norman_Castle

Trek still have hub geared, belt drive bikes on their site.
http://www.trekbikes.com/uk/en/bikes/town/recreation/soho/

Johnmcl7

If you look carefully (it is misleading) the only bike there is a chain driven one even though the pictures below show a belt drive. For some reason the Trek Soho 2010 is a belt drive but the 2011 uses a chain which I had completely missed until the bike shop pointed it out (I have the Soho Deluxe 2011 which keeps the belt drive). There are no new 2012 models with a carbon belt drive I'm aware of to replace the older ones and certainly the shop has no gear hub bikes.

John