A brand new Smartabike but an old and clueless owner!

[whispertread]

I've just treated myself to a brand new Smartabike called Model LX8
I'm still grinning from the buzz I get from riding around getting used to it, but I'm suddenly aware that I know nothing about the way modern bikes have strange band-brakes on the back wheel and the gears are a very long way from the Sturmey Archer 3-Speed type of my youth and look nothing like a Shimano setup.

It has an 8 speed hub gear and I'm reluctant to undo anything if I should wish to remove the back wheel to have a new tyre fitted for fear of not being able to get it back together again. The Handbook doesn't cover the running gear of the bike, only the electrics. I've worked out how to remove the front wheel and disconnect the wiring from the hub motor, once I made a call to the Retailer so that bit's sorted. Perhaps I really should let an expert do the job for me, but I like to be fairly independent of paying labour charges when I might be able to DIY with a little patience.

I wish there was a diagram guide or pictorial one where the parts I should undo are shown and how to adjust them when re-assembling.

I want to fit a pair of puncture resistant tyres but I don't know if the wheel comes out leaving the gears behind or whether I have to remove a lever; cable; bolt etc and then how do I disconnect the hub gear so it can still work through gears 1-8 properly when I put it back?

Anyone out there done this job already and could point me in the direction of what not to play about with.

I notice the chain isn't of the split-able spring-link type, it's continuous like a motorcycle chain so links would need a link-extractor and re-riveter to join it back up, so it must be possible to remove the wheel without separating the chain. It's all a bit scary. So I thought I'd ask on here to see if someone with expert knowledge can tell me how easy it is (or should be) providing I don't go and snap something under warranty!
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Thanks.
Whispertread

 

[Dyno]

Hi, I own the Smarta GT, but see from the pictures of the LX8 that the gears differ. The Back Wheel should be reasonably straight forward to remove making sure the wires are disconnected prior to full removal. You should not need to unlink the chain, just unhook it after the wheel is removed from the frame slightly.
Without experience of this bike, my recommendation is to speak with the company you purchased the bike from and ask their advice.
If its the Electric Transport Shop where I purchased mine from, their customer service is excellent.

Maybe someone else has experience with this type of bike.

 

[tillson]

Looking at the website for your bike, that rear wheel should come out reasonably easily.

The gear changer cable hooks onto an actuator at the gear hub end, you'll see what I mean if you take a close look. The cable sheath terminates in a black metal bracket which faces towards the front of the bike, and then the inner cable continues and wraps around the actuator. On the end of the inner cable will be a clamp which hooks into the the actuator.

Put the bike in first gear, locate the inner cable clamp and actuator and turn it against the spring action in an anti-clockwise direction. This will cause the cable to become slack and you can then un-hook the inner cable. Pull the outer sheath from the rubber grommet and the wheel can then be taken out of the bike.

There are far better and much clearer instruction on how to do this posted by other members on here, but I can't find them at the moment. If the above doesn't make sense, it will be worth spending 10 minutes searching this forum.

I find putting the rear wheel back in to be a real test of my patience. I can never seem to get it central and achieve an even distance from each brake pad. I always end up with the wheel closer to the brake pad on one side than the other. I dream of a perfectly centralised wheel!

 

[whispertread]

Thanks Tillson and to Dyno. This is just the type of info I was hoping for. I was wondering whether it should be disconnected in 1st gear or 8th as either end of the range looks to be just as impossible to remove the cable when I didn't know what you must undo first.

I wasn't even aware there were brake pads to be aligned on replacement of the wheel. It doesn't sound very easy to me. That's no reflection on your description I hasten to add. It's just that the system seems very clumsy to me.

In answer to Dyno's suggestion that I contact the company, well, I have already done that, and they're very helpful but the combination of the fact that I am slightly deaf and on the phone, instructions are very difficult to follow when someone isn't able to look at what you're looking at - and you have no pictures or diagrams the whole thing done by remote control is a very hit and miss affair.

The guy who built this bike straight out of the crate from stock is very skilled and had it all assembled in a very short time but he's on holiday and I really think that if I tried to remove that wheel I'd end up not being able to get it back. I wish I could watch someone do the job. Monkey see, Monkey Do, type of thing. I'd be on to it like a shot then.

Another thing that worries me is the undoing of the cable clamp, as I'm not sure whether you mean the threaded adjuster and if I do slacken off the right screw, how will I know when it has been replaced that the setting will allow full range of gear selection. I bet it's very sensitive to being exactly in the position for optimum gear shifting.

I really wish there was a video somewhere so I could see it done and explained. I doubt if anything is on YouTube yet as these bikes are so new. Again I'm not sure what you mean by the bit where you said "Pull the outer sheath from the rubber grommet and the wheel can then be taken out of the bike." Do you mean the cable outer? And why must that be removed once you've unhooked the cable nipple from the actuator? Having removed the gear change system, what about that darned band-brake? Does that come away with the wheel as a single unit?
It's all so disguised and I can't seem to fathom it from straight inspection. It's too neat really.

Last week I had a complex electrical switch fall into about 30 pieces in my hand, just from undoing the wrong screw when trying to un-wire it. I had to chuck it and start again buying a new switch of a different design.

You have to be really sure of what you're doing when dismantling brake and gear systems. I wish the rear wheel had been instant quick- release like the back wheel on a BMW Motorcycle - 4 bolts and off it comes. A tyre swap takes about 5 minutes!

Thanks again for your help. I'll see if I can find other references as you have mentioned on the forum.
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Cheers
Whispertread.

 

[tillson]

I have just noticed that you mention, "band brakes" on the rear of your bike. I'm not sure what these are or weather they will make wheel removal easier or mor difficult.

When I talk about, "brake pads" I just mean plain old brake blocks on rim type brakes, nothing fancy.

 

[whispertread]

Thank you Tillson - well spotted!
Yes you're dead right, it's not the normal calliper brakes on the rear wheel, but the front has normal callipers.

The rear is difficult to describe, it's a brake band that tightens up on a drum. It's like the negative of a drum brake on a car where you have shoes inside a drum that squeeze outwards against the drum to friction stop the wheel, but instead the shoes are on the outside of a drum and the cable pulls the "band" tighter to grip the drum and friction stop the wheel that way.

I expect it's a standard system but I don't know what it's called. Never seen one before. It works very well.

I just tried to post a jpg photo of it up here as an attachment, I hope it did "take". Have a look at the setup from the angle of down behind and below the left hub. The cable pulls on a lever and moves it forwards to the front of the bike. I think the black plastic part of the hub is the brake system.

There's a big alluminium disk with large teeth on the inside of the spokes that is part of the hub but they don't appear to mesh with anything, it's a very strange looking setup. It looks like an ABS system !
Thanks for your interest in solving this problem for me.

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Whispertread

 

[vhfman]

Hi Whispertread
I do not have any direct information about your specific bike. Nor do I have experience of modern hub gears. But the hub gears and roller brakes used on your bike appear to be standard Shimano IM70 fan cooled hub brake on the Nexus 8 Hub.
I Just did a Google search and found these links which my help you, or not!

YouTube - How to remove a Shimano Nexus or Alfine hub equipped wheel from your bike

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/RollerBrake/BR_IM70_R/SI-75E0E-EN_v1_m56577569830689655.pdf

Shimano Nexus 7-speed and 8-speed Internal Gear Hubs-Technical data

Google (or any other search engine) is your friend.

If these links don't help I am sure there are some members on the forum that have the same hub brake setup that can enlighten you more.

 

[flecc]

I'm amazed and disappointed that it has a band brake, these were abandoned some years ago and were normally only fitted on the cheapest Chinese made bikes. Main disadvantage is that after a while they tend to squeal and little can be done about that.

Modern bikes have either rim brakes in various kinds, disc brakes or roller hub brakes. Band brakes and car style hub brakes with shoes inside a drum have all but disappeared.
.

 

[whispertread]

VHF Man thanks a million those three links look very promising indeed. I'll go investigate them straight away.
I'm very grateful to you for that bit of information.

Another view of the rear hub I failed to spot when taking that photo was that on the side of the brake it has the name stamped and says SHIMANO Nexave. BR-IM 70-R
Inter M Multi-condition. Quite a model number!
It's a shame that the concept is out of date according to another poster here.

I think I'll go look at all your links and see what I can learn from them. Also removal of the hub gear probably comes out with the wheel in once piece, so should be a matter of disconnecting the cable and making a small paint mark on the cable itself so I know where to clamp it back when re-assembling. I only need to do this once as I want to put new tyres on the bike.

If I do get in a mess, I'll simply return the bike to Bristol and give them the two new tyres and ask them to fit them and I'll collect it the next day.

Thanks again for your potentially very useful info.
I'll keep watching the thread in case someone else comes up with more handy tips.
Cheers and Beers
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Whispertread

Hi Whispertread
I do not have any direct information about your specific bike. Nor do I have experience of modern hub gears. But the hub gears and roller brakes used on your bike appear to be standard Shimano IM70 fan cooled hub brake on the Nexus 8 Hub.
I Just did a Google search and found these links which my help you, or not!

YouTube - How to remove a Shimano Nexus or Alfine hub equipped wheel from your bike

http://techdocs.shimano.com/media/techdocs/content/cycle/SI/RollerBrake/BR_IM70_R/SI-75E0E-EN_v1_m56577569830689655.pdf

Shimano Nexus 7-speed and 8-speed Internal Gear Hubs-Technical data

Google (or any other search engine) is your friend.

If these links don't help I am sure there are some members on the forum that have the same hub brake setup that can enlighten you more.

 

[flecc]

That's a relief, it's not a band brake at all as you'd said, it's a roller brake.

This type has rollers and ramps, and when it's applied, the rollers run up the ramps and start to wedge against the surround, giving the braking action. Not very fast acting, but they are almost maintenance free and very reliable.

This webpage has an exploded diagram of the whole assembly as fitted to a derailleur gear hub. The optional cooling disc is in place on that diagram, which you might not have fitted
.

 

[whispertread]

Thanks are due to you too. I will go and check out that link as it could be useful.

I've just watched You Tube video advised by vhfman and the demonstration was really good. I would never have known from normal visual inspection about the tiny hole that you have to wind the gear change quadrant round to release the cable. Also it advised putting the gear change on the twist-grip, to position Gear4 as this aligns two little yellow marks on the quadrant, one moving and one static indicating the middle gear position. That could prove very useful on re assembly.

I immediately went and turned my bike upside down and had a look at the gear change cable termination point, and sure enough there's a tiny hole which a very thin Allen key or needle point bradawl can be pushed into and then you lever up the rotating quadrant to slacken the cable and then pull the cable nipple stud out of its housing. So easy when you see how it's done!

Next and final job would be to undo the brake-cable on the other side and unscrew the cable adjuster stay because the arm which the adjuster is held by, is attached to the hub and bolted to a flange on the frame-spar. Simple one nut and bolt to undo and the stay arm would come away with the wheel as it's part of the hub brake mechanism.

Finally the axle would be removed from frame lugs and chain slipped off and Robert is your Father's brother!

I think I can manage it now. So again thanks to all for your kind help. You've saved the day. I think I can go order those two armoured tyres now.

Regards to all
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Whispertread