Thorn Cycles Forum
Technical => General Technical => Topic started by: neil_p on May 05, 2011, 08:59:17 am
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Hi all
I've had my Thorn Rohloff for about 4 years now, and it has started to feel a bit "sluggish". I have changed the oil every year (last month was the most recent change), so, I'm wondering what else might be wearing out?
Pedals? - I have Speedplay Frog pedals, which were second hand (and well used) when purchased 4 years ago. They have since had 4000 miles use. This is my first "proper" bike, so I don't know how long a pedal should last.
Tyres? - My tyres and tubes are original Panaracer Pasela TG. There is still some tread left, but perhaps the rubber starts to break down after 4000 miles?
Chain? - at what point does it need replacing? The thorn manual implies you can keep adjusting the EBB, then remove a link and reset the EBB. I have not yet removed a link, so should there be plenty of life left in it?
Bottom bracket? - (Shimano Hollowtech I think) - what is the life of these?
Thanks all
Neil
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Neil, I am into year 5 with my RST, on my 3rd chain and second rear sprocket, still on original BB and have turned the chainring, bike does an average of 5k miles/year. Tyres, i run contis I did not like the pasela tyres at all, too fragile, I threw them away after 6 months. The pedals should turn freely with no play in the bearings. Keep your tyre pressure high, 70 front and 90 psi rear for me, maybe its not the bike ;)
ta
Dave
www.davesbikeshed.co.uk
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Neil, I am into year 5 with my RST, on my 3rd chain and second rear sprocket, still on original BB and have turned the chainring, bike does an average of 5k miles/year. Tyres, i run contis I did not like the pasela tyres at all, too fragile, I threw them away after 6 months. The pedals should turn freely with no play in the bearings. Keep your tyre pressure high, 70 front and 90 psi rear for me, maybe its not the bike ;)
ta
Dave
www.davesbikeshed.co.uk
Which conti tyres are you using? I'm after something light and puncture proof for commuting/sportives.
My tyres/tubes never used to need pumping up more than once every 3 months, but they now seem to need pumping up every fortnight. They don't have punctures - but can the rubber perish over time and start to lose air?
Based on what you say you're replacing the chain every couple of years, so approx every 10k miles? That means I should have another few miles yet in my chain.
I'm pretty sure it is the bike (not me!) ;D
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Sorry if this is too trivial, but do make sure you don't have a brake shoe rubbing against the rim! Another problem I had was that one of the bolts that attaches a fender stay to the fender was rubbing the tire a little. Just spin the wheels and make sure they're free of anything gross like that.
Again, sorry if this is just too obvious, but just in case...
Jim
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Cheers Jim... thanks for the reminder. I did fit new brake pads recently, and didn't check for pad rub. I'll do that tonight!
I'm pretty sure the pedals need replacing... they were pretty worn when I bought them on ebay 3 years ago. I think I'll replace them and see how it feels.
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My guess would be the tyres. Tyres will lose a lot of air in 3 months. Even if it is only 10% a month that is a big change and it will significantly alter the contact area the tyre makes with the road. Tubes and valves may also begin to lose air although I am not aware of any long term tests.
Many people love Panaracer TGs as they are light and relatively puncture resistant. But, the sidewalls are very thin (mine ripped after 150 miles) and I now use standard marathons. You must keep them hard to maintain their structure.
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Chain lubrication is another interesting puzzle. I started using Progold Prolink & seemed to notice some improvement. Then my chain fell off so I decided to switch chains - my idea is to rotate a few chains. Maybe that way I can clean chains well when they're off the bike. I'm still trying to work out a good system.
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My guess would be the tyres. Tyres will lose a lot of air in 3 months. Even if it is only 10% a month that is a big change and it will significantly alter the contact area the tyre makes with the road. Tubes and valves may also begin to lose air although I am not aware of any long term tests.
Many people love Panaracer TGs as they are light and relatively puncture resistant. But, the sidewalls are very thin (mine ripped after 150 miles) and I now use standard marathons. You must keep them hard to maintain their structure.
When you suggest it'll be the tyres, do you mean they need pumping up, or replacing? Any suggested pressure for Pasela TGs?
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When you suggest it'll be the tires, do you mean they need pumping up, or replacing? Any suggested pressure for Pasela TGs?
Well so long as they are hard they should be OK. There is a possibility that if they are worn they might not be keeping there shape as well as when new -but that is speculation on my part. The max pressure for 26 x 1.5 is 40-65 psi according to this table:
http://www.panaracer.com/eng/products/speclist/urban.html
I would definitely go for 65 psi which will feel hard. I run my marathons at 80 psi on the back and 60 at the front but they are rated up to 100 psi.
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I reckon the quickest change to the feel of a bike is by changing to heavier or lighter tyres/tubes/rims.
You will feel the rotating weight change immediately in the handling.
It is possible your tyres may be degrading, exposure to sunlight is damaging to some materials.
Give the wheels a spin and check the tyre shape is regular, no twists, flat spots or bulges.
I recently fitted new inner tubes, extra extra light Schwalbes and they made a slight difference (an improvement).
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I reckon the quickest change to the feel of a bike is by changing to heavier or lighter tyres/tubes/rims.
You will feel the rotating weight change immediately in the handling.
Totally agree!!!
Re chain replacement - It has been covered on this forum several times and at the end of the day it is a personal preference thing. However my opinion is given the single chain ring and single sprocket you can pretty much ignore the normal rules about replacing the chain. 'Stretch' simply don't matter if you only have one sprocket. I ran my first chain until I could see significant ware in the chain ring (~12000miles) at which point I replaced the chain and reversed sprocket and chain ring. My second chain is now on about 14,000 miles. I intend to carry on running the same chain until I ware out the whole system. (It will be the Aluminium chain ring that fails first for me) It doesn't look like failing any time soon! I still have total confidence in the chain and chain ring - Last weekend I did 200 mile overnighter without any concerns . I have all the replacement part standing by in my garage but I don't think I will be reaching for them until next year! So if I do make it to next year that will mean that I will have cycled approx 30,000 road miles on 2 chains, 1 sprocket and 1 chain ring. Which is pretty good value for money!
'Sluggish' bike - For me personally I find two reasons why I am going slower than normal. If it is not under inflated tyres then I know I have over inflated my waist line! ;)
Stutho
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I must say that i'm very pleased with the lack of long term maintenance required by my three year old RT.
I've replace brake inserts twice on the front (once due to being worn out and then a new set that i run with my winter wheel (dynohub)).
I've replaced the chain once and reversed the sprocket and chainring at the same time (i think the sprocket will be the first thing to go pop - i also have replacement sprocket / chainring and chain in stock!. The chainring looks virtually unworn to my eye!
And thats it. Original bottom bracket, eccentric, rims etc. The rear wheel is as straight and true as the day i bought the bike and should have plenty of miles to go yet - a real credit to the sjs wheel builder. I've replaced one tyre due to wear and another due to a bulge.
I'm watching the forum with interest at the moment due to a change of circumstances that means going away with a heavy load is not going to be possible in the near future, so pure road use will be all it is used for (quite a lot of it though), which means my mind has been telling me to consider some lighter (within reason) rims and tyres...... mmmmmm expensive.
Anyway, hardly any maintenance and 17100 miles of use. Fantastic - exactly why i bought the beauty!
Gary.
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I ran my first chain until I could see significant ware in the chain ring (~12000miles) at which point I replaced the chain and reversed sprocket and chain ring. My second chain is now on about 14,000 miles. I intend to carry on running the same chain until I ware out the whole system.
'Sluggish' bike - For me personally I find two reasons why I am going slower than normal. If it is not under inflated tyres then I know I have over inflated my waist line! ;)
Cheers for the ballpark figures Stutho. I'm in the process of working out how many miles I have done on my Thorn (4000 was a guesstimate). If a chain and sprocket does 10, 12 or even 15k before replacement and reversal respectively, mine are only halfway toward that distance. I've just googled "worn chainring images".... mine have no visible wear compaired to the sharkfins you see.... so they must be doing ok.
Thankfully my waistine has shrunk recently ;D
I got into doing Sportives last year, and have been training seriously for them this season. I do love dropping the roadies on their 8kg carbon bikes.... they see my steel frame, rohloff, mudguards and racks and presume I'm on a camping holiday... ;D ;D ;D
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they see my steel frame, rohloff, mudguards and racks and presume I'm on a camping holiday... ;D ;D ;D
Hello, campers!
I'm far too polite to drop roadies, of course. [sniff]
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the conti's i run are sport contact with a guarantee of replacement within a year if they puncture - which they do, I am on about my 6th after original purchase maybe I'm just tight ;D
http://www.wiggle.co.uk/continental-sportcontact-city-road-tyre-and-tube-set/ (http://www.wiggle.co.uk/continental-sportcontact-city-road-tyre-and-tube-set/)
other bike shops are of course available, and I have no idea if everyone does the guarantee or just the big W
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the conti's i run are sport contact with a guarantee of replacement within a year if they puncture - which they do, I am on about my 6th after original purchase maybe I'm just tight ;D
http://www.wiggle.co.uk/continental-sportcontact-city-road-tyre-and-tube-set/ (http://www.wiggle.co.uk/continental-sportcontact-city-road-tyre-and-tube-set/)
other bike shops are of course available, and I have no idea if everyone does the guarantee or just the big W
So do you mean, you bought one set, with warranty, and have had 5 or 6 replacement tires since then, all under warranty? In what timeframe has that been?
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One set with warranty bought about 3 - 4 years ago
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So you've ended up with one paid for set of tyres in effect lasting 4 years.... but still with the hassle of replacing them several times. I'm not sure I'd want that hassle?
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but I dont mind ;D I like running quality, fast rubber on my RST these are best for what i do. safe cycling D
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So if I do make it to next year that will mean that I will have cycled approx 30,000 road miles on 2 chains, 1 sprocket and 1 chain ring. Which is pretty good value for money!
I've just been advised by SJS, that if my chain has stretched by 1% (i.e. 12 full links now measures 12 1/8" or more), I should replace the chain and reverse sprocket and chanring. My chain has indeed stretched that much after 5k miles... which means 2 chains, 1 sprocket and 1 chainring will last me 10k miles (a third of what you have achieved). Can that be right? It seems quite a difference.
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I've just been advised by SJS, that if my chain has stretched by 1% (i.e. 12 full links now measures 12 1/8" or more), I should replace the chain and reverse sprocket and chain ring. My chain has indeed stretched that much after 5k miles... which means 2 chains, 1 sprocket and 1 chainring will last me 10k miles (a third of what you have achieved). Can that be right? It seems quite a difference.
The thing is I don't agree that you need to change the chain until there is significant wear to the sprocket and / or the chain ring - or the chain snaps (which it wont). What is achieved by swapping out the chain early? You may extend the life of the sprocket / chain ring BUT you will be paying more money out overall on new chains.
When I used to ride a dérailleur I used to be extra fussy about the extension on my chain but now I ride with a speedhub I take absolutely no notice of the chain extension, I simply don't see any advantage to switching out the chain early. I would rather just let all the parts of the ware together. One concession I do make however is to only use high quality chains.
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The thing is I don't agree that you need to change the chain until there is significant wear to the sprocket and / or the chain ring - or the chain snaps (which it wont). What is achieved by swapping out the chain early? You may extend the life of the sprocket / chain ring BUT you will be paying more money out overall on new chains.
When I used to ride a dérailleur I used to be extra fussy about the extension on my chain but now I ride with a speedhub I take absolutely no notice of the chain extension, I simply don't see any advantage to switching out the chain early. I would rather just let all the parts of the ware together. One concession I do make however is to only use high quality chains.
I agree with everything you say.... but I'm baffled why SJS would want me to replace chain and reverse sprocket/chainring so soon... their suggestion will triple my transmission running costs from £90 (approx for new chain, sprocket and chainring) per 30k miles to £90 per 10k miles. Still better than deraileur running costs, but even still...
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I would let everything wear out for the first instance then you have a real baseline to measure costs and wear against.
It will also probably work out much cheaper.
If you saw the picture of Helen's (Take on Africa) (http://takeonafrica.com/) worn rear cog then you have a target to aim for!
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Now that is one worn sprocket! And something to aspire to.
Strangely, the chainring on my RT shows very little wear. the sprocket is worn but still has plenty of life in it.
I replaced the chain when i reversed the chainring and sprocket at 12000 miles. The bike has now covered almost 18000 miles and the transmission will be run into the ground
I don't bother with expensive chains. I expect to have used two chains costing less than a fiver each, over 24-25000 miles.
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I have a surly stainless steel chainring and since the rohloff sprocket looks a lot like stainless to me, I use a stainless steel single speed chain, I reckon having all components made of similar hardness materials should result in more even wear, only done 5,000 miles so far, and no visible or measurable wear yet.
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Strangely, the chainring on my RT shows very little wear. the sprocket is worn but still has plenty of life in it
For me it is the other way round the chain-ring will fail first - the sprocket is looking well used but the chain-ring is knackered but serviceable.