Mambo (I mean puncture) No.5

JohnInStockie

Esteemed Pedelecer
Nov 10, 2006
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Stockport, SK7
Well some people have all the luck they say, unfortunately not me then (amongst others I know). "Enjoyed" my 5th puncture in 12 months on my second set of Marathon+.

This time it was a 2" nail, stuck so well into the tyre/wheel that it interfered with the mudguards and knocked them out too. Rush hour traffic, 5 miles from home, 6 miles from work, slight rain.........

Tried my Vittoria 'tyreweld' type stuff, did nothing...hole too big :mad: Hub gears and brakes so barrier cream on, disconnect everything, take of the Reelight, pull out the gearing pin, undo the wheel and change the tube, then do the reverse of the above.

The crank in the back wheel is wobbly, so disconnect everything again, and finger tighten the hub crank. Put everything back on the bike again and pump up to the 65psi I like and Whallah!! A mere 1 hour has passed .... wipe my hands as best I can with my swarfega wipes and get back on the road to work ....

Bad news........ the chain keeps slipping.....???

Dont know whats wrong with it, it feels as if the chain is slipping but the chain is not slipping, its the gears that are trying to change but arent changing and I'm not even trying to change gears. The lines are spot on..:confused:

I think I'm going to go for solid tyres, I am truly sick of punctures, and I've somehow strained my back in attempting the roadside repair :(

Its not easy being green they say...

John
 

JohnInStockie

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Nov 10, 2006
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Stockport, SK7
Does anyone know what could be causing the hub gears to slip internally, is this usually an adjustment thing, or do I need a bike shop?

Thanks guys

John
 

JohnInStockie

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Nov 10, 2006
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Stockport, SK7
How old is your chain? It could be worn. Check by measuring it for "stretch".
I think it must be something to do with the chain or the sprockets in some way, maybe the tensioner, but I cant actually see the chain slipping when the 'slip' occurs :(

I wonder if somehow, something got into the internal gear chamber whilst I was repairing the puncture. Can these hub gears internals be flushed clean in some way?

John
 

JohnInStockie

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Nov 10, 2006
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Im going to continue the investigation tomorrow night, and I will post what I find, if I find anything :eek:

Thanks for the advice
 

JohnInStockie

Esteemed Pedelecer
Nov 10, 2006
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Stockport, SK7
SRAM P5 Advice??

Can anyone advise on hub gears?

After repairing my puncture at the roadside, I havent been able to use my bike.

When in gears 1 to 4 everything is ok, but as soon as I go into 5 the gears constantly crack and bang like it just cant get into gear.

Could this be caused by some detrius getting into the gear chamber? Anyone ever had anything like this?

Can the internals of this system be accessed in any way?

Thanks guys


John
 

prState

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Jun 14, 2007
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Las Vegas, Nevada
Don't know if this will help, but on my lafree, aside from getting lines aligned on the hub sometimes there is a certain allowance to how pushed into the dropouts the rear tire can go.

Yes, the tire needs to roll straight, but you can also somewhat adjust how far back the tire sits, or doesn't.

The lax way is simply put on the rear wheel, check to see it's rolling straight, and tighten the nuts.

The other way I've done it, is to put on the rear wheel, and sit on the pannier forcing the wheel into the slots more and then tighten the nuts. If necessary loosen slightly to get the wheel rolling straight.

At times, this has seemed to make a difference in chain staying on, or gear shifting. Hope that makes some sense, or better yet helps.
 

JohnInStockie

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Nov 10, 2006
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Stockport, SK7
Thanks for that prState. Yes I'd already discovered that. Last time I had a puncture I noticed that the chain was a bit slack and the 'slide back in the drop-outs' technique wasnt working, so I tightened the spring in the chain tensioner 1 notch around to make it a bit better as it seemed quite slack to me. Have you looked at that?
 

flecc

Member
Oct 25, 2006
44,208
20,372
When in gears 1 to 4 everything is ok, but as soon as I go into 5 the gears constantly crack and bang like it just cant get into gear.

Could this be caused by some detrius getting into the gear chamber? Anyone ever had anything like this?

Can the internals of this system be accessed in any way?

Thanks guys


John
I'm not quite clear what you mean here John. Does it actually get into top gear and then while pedalling making a banging and cracking sound, or does it just slip, the gear not engaging at all?

In other words, can you propel the bike forwards in top gear without the pedals slipping, just making those noises?
.
 
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JohnInStockie

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Nov 10, 2006
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Stockport, SK7
Made it worse !!

Ah well A for effort but U for achievement :(

tried to figure out whats wrong, no luck. the tension in the cable is bang on, its something internal.

@Flecc - eariler when selecting the 5th, immediately it would slip in the gear, only allowing you to propel yourself forward erratically with constant slipping and cracking.

Now it doesnt change gear at all, and it seems as if the nut on the drive side that you tighten finger tight, is constantly coming loose as the bike freewheels. When upsde down you can see it best, after pedaling by hand, when you stop the bike freewheels, but on every rotation it 'turns' the pedals, as if something is making contact. The back wheel then can wobble about on the central shaft.

John
 

flecc

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Oct 25, 2006
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It sounds as though the left hand internal nut that retains the complete insert in the hub shell has come loose when you took the wheel out John. This will throw the hub out of registration, meaning the bearings will have slack allowing wobble, and the changer shafts from the actuator won't register correctly.

I think it's best that you take it into a dealer with hub gear knowledge (older the better) to be set up correctly.

It's probably the half nut numbered 3 in the diagram below that's come away from it's correct position, and the large ring bearing number 7 that's allowing the wheel to flop about:

SRAM P5 Diagram.jpg

P.S. Your's may be different in that I believe it has the roller brake version of the hub, but the principle is the same.
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oldosc

Pedelecer
May 12, 2008
207
10
It sounds as though the left hand internal nut that retains the complete insert in the hub shell has come loose when you took the wheel out John. This will throw the hub out of registration, meaning the bearings will have slack allowing wobble, and the changer shafts from the actuator won't register correctly.

I think it's best that you take it into a dealer with hub gear knowledge (older the better) to be set up correctly.

It's probably the half nut numbered 3 in the diagram below that's come away from it's correct position, and the large ring bearing number 7 that's allowing the wheel to flop about:

View attachment 334

P.S. Your's may be different in that I believe it has the roller brake version of the hub, but the principle is the same.
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Flecc...is this a Homesion deduction, or have you had occur before...looking at your exposition, I can see how it makes sence...In that case how did this nut ,'become' loose on taking out the wheel, ( makes me shudder when I have just done the same thing)
 

JohnInStockie

Esteemed Pedelecer
Nov 10, 2006
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Stockport, SK7
It's probably the half nut numbered 3 in the diagram below that's come away from it's correct position, and the large ring bearing number 7 that's allowing the wheel to flop about.
Thanks Flecc thats absolutely bang on. Its that half nut that has constantly been coming loose now every time I take the wheel off, but oddly has been fine while the wheel was on, Ive had to 'finger tighen' that at least 4 times this year.

To confound matters I decided to 'learn' how these work and took out some of the internals (just the half nut and its spring, and the no7 and the big spring behind, and the cog below that - then my bottle went and I put it all back). I was hoping I would see a stone or something like that causing the issue, but was soon out of my depth.

Thanks very much for the excellent info and advice Flecc.

John
 

flecc

Member
Oct 25, 2006
44,208
20,372
Flecc...is this a Homesion deduction, or have you had occur before...looking at your exposition, I can see how it makes sence...In that case how did this nut ,'become' loose on taking out the wheel, ( makes me shudder when I have just done the same thing)
It's impossible to make a 100% diagnosis at a distance of course oldosc, but that is the most common of the two possibilities that lead to the same symptoms. That half nut is actually a locknut against a second half nut but if not locked up firmly enough, it and the inner nut can spin together on the thread, slackening the left hand bearing cone.

There's two ways that happens on the P5. One is that it's rotated by uneven pressure against the dropout slots as the wheel is withdrawn, starting the turn. The other is if the hub has a brake as well as I think John's has, and that's where the brake back plate is allowed to turn on the spindle and drag round the nuts. The brakes have their own retaining nut and they can all turn together very easily.

Any of these allow the complete inner assembly to drift to the right.

The less common possibility is the right hand cone number 18 turning on the spindle and loosening that side bearing, but that's not so likely to upset the gear engagement registration that John's suffering.

As you can tell, I'm very familiar with these hubs.

As for your one, it's not an SRAM P5 hub so these details don't apply.
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flecc

Member
Oct 25, 2006
44,208
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Thanks Flecc thats absolutely bang on. Its that half nut that has constantly been coming loose now every time I take the wheel off, but oddly has been fine while the wheel was on, Ive had to 'finger tighen' that at least 4 times this year.

To confound matters I decided to 'learn' how these work and took out some of the internals (just the half nut and its spring, and the no7 and the big spring behind, and the cog below that - then my bottle went and I put it all back). I was hoping I would see a stone or something like that causing the issue, but was soon out of my depth.

Thanks very much for the excellent info and advice Flecc.

John
It is tricky to get that half nut reliably locked onto the inner John, but as you say, it's no problem when the wheel is in since the wheel nut locks everything into place.

As you can see from the exploded diagram, the internals are not to be lightly messed with. Repair is commonly by replacing the whole inner assembly, and that's true of all makes these days. That shouldn't be necessary now of course, it should be amenable to being reset into position.
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JohnInStockie

Esteemed Pedelecer
Nov 10, 2006
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Stockport, SK7
The bike shop I have tried are having real trouble with this. They've said that an 'inner bearing' is broken, and they have had 2 incorrect parts delivered thus far.

They have resorted to photographing the parts that they need and sending these to Germany!!

I dont know how much this will cost, but it does seem that these are really quite hard to get repaired (unfortunately) :(

John
 

flecc

Member
Oct 25, 2006
44,208
20,372
The problem is the lack of dealers experienced with hub gears now John, since the mountain bike with derailleurs craze took over the utility market for so long.

The best bet is a man nearing retirement or one of the very few firms who specialise.

We have one in London, the Brixton Cycle Co-operative who've specialised in hub gear work, but they are a rarity.

The sad thing is that I recently chucked out all the components you need for the P5, left over after a cog failure in one of mine. Hopefully Sachs (SRAM) will get your parts over quickly.
.
 

JohnInStockie

Esteemed Pedelecer
Nov 10, 2006
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0
Stockport, SK7
Just thought Id post an update.

Still off the road. SRAM now apparently do not recognise the part that has broken (the bike shop told me with incredularity) claiming it does not match any of the 4 SRAM P5 design parts.

I am going to take your diagram (above) into them tonight, otherwise I am at a loss (spares anyone??).

John

PS - any advice greatfully received.
 

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