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Triple chainset replacement
#1
Hi, new to the forum, need some tech advice:

1) is it normal for the teeth on the same chainring to have different profiles - some are pointed and others shorter and squarer. This is a new Triple LASCO I am looking at in a shop.

2) How do I know if any new chainset I buy, will match my existing spindle? The chainset I have currently fitted is an SR SUNTOUR ZR 120, does that mean the square hole is 12mm?

Many thanks.
Zak
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#2
(01-20-2014, 08:19 PM)zak rider Wrote:  Hi, new to the forum, need some tech advice:

1) is it normal for the teeth on the same chainring to have different profiles - some are pointed and others shorter and squarer. This is a new Triple LASCO I am looking at in a shop.

Yes, it is. The teeth have odd shapes to make shifting better, there are also ramps and pins and whatnot on the chain rings.

Quote:2) How do I know if any new chainset I buy, will match my existing spindle? The chainset I have currently fitted is an SR SUNTOUR ZR 120, does that mean the square hole is 12mm?

I have no clue what the type numbers mean... In order to decide for a working combination, there are some sites like
http://sheldonbrown.com/bbsize.html
that can help you to pick a working combination. Basically you need to measure the axle length and then pick a crank set - or get a new matching combination. It can be tricky though...
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#3
Zak; why do you want to replace the crank set? From that point we can offer some advice.
Nigel
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#4
(01-21-2014, 10:55 AM)Joe_W Wrote:  
(01-20-2014, 08:19 PM)zak rider Wrote:  Hi, new to the forum, need some tech advice:

1) is it normal for the teeth on the same chainring to have different profiles - some are pointed and others shorter and squarer. This is a new Triple LASCO I am looking at in a shop.

Yes, it is. The teeth have odd shapes to make shifting better, there are also ramps and pins and whatnot on the chain rings.

Quote:2) How do I know if any new chainset I buy, will match my existing spindle? The chainset I have currently fitted is an SR SUNTOUR ZR 120, does that mean the square hole is 12mm?

I have no clue what the type numbers mean... In order to decide for a working combination, there are some sites like
http://sheldonbrown.com/bbsize.html
that can help you to pick a working combination. Basically you need to measure the axle length and then pick a crank set - or get a new matching combination. It can be tricky though...

Thanks joe.
Reply
#5
(01-21-2014, 05:00 PM)nfmisso Wrote:  Zak; why do you want to replace the crank set? From that point we can offer some advice.

Hi Nigel,
i just replaced the rear cassette and chain last week and assumed its best to replace the three components at the same time - rear cogs, chain and chainset. But from researching this topic widely I read that if the new chain isn't slipping then there is no need to change the chainset? Here is a photo of the teeth on the chainset. Do you think I should ride it and if only change the chainset if the chain slips? Would certainly save me a lot of hassle as I am having trouble finding a set...
Jac
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#6
Hi Zak;

The teeth look fine. If it works, I would not change. I have only changed the crankset on my World Tourist to get rid of the FFS. And on our T50, I changed the middle chainring because it was bent during transport. I also swapped the T50's granny ring from 28T to 26T to get a lower bottom gear for steep hills. I have never had a wear out issue with chainrings...

From the corrosion, it appears that the chain rings are steel - you can check with a magnet; steel ones will attract a magnet, aluminum will not. If steel, they are not likely to wear out in our lifetimes.

To get rid of the rust on the steel rings, you can rub them with a wad of aluminum foil dipped in water, then wipe them with your favorite chain lubricant.
Nigel
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#7
(01-23-2014, 09:44 PM)nfmisso Wrote:  Hi Zak;

The teeth look fine. If it works, I would not change. I have only changed the crankset on my World Tourist to get rid of the FFS. And on our T50, I changed the middle chainring because it was bent during transport. I also swapped the T50's granny ring from 28T to 26T to get a lower bottom gear for steep hills. I have never had a wear out issue with chainrings...

From the corrosion, it appears that the chain rings are steel - you can check with a magnet; steel ones will attract a magnet, aluminum will not. If steel, they are not likely to wear out in our lifetimes.

To get rid of the rust on the steel rings, you can rub them with a wad of aluminum foil dipped in water, then wipe them with your favorite chain lubricant.

Hi Nigel,
Thanks a lot for the tips, will ride and keep an eye on it.
Yes steel, heavy as anything! As for favourite chain lubricant, what do you recommend? I live in the Seychelles, we don't have a bike shop, and people import stuff directly from suppliers overseas. Humidity is high and most roads are coastal, so rain, salt and earth get onto the chain and everything else. Actually, I need a beginner's guide to basic ongoing bike maintenance: post-ride cleaning, chain lubrication, derailleurs, how to determine height of saddle relative to handlebars for my height, what horizontal angle the seat should be pitched at for optimum comfort, what road tires I should fit ...
Zak
(01-23-2014, 08:28 PM)zak rider Wrote:  
(01-21-2014, 05:00 PM)nfmisso Wrote:  Zak; why do you want to replace the crank set? From that point we can offer some advice.

Hi Nigel,
i just replaced the rear cassette and chain last week and assumed its best to replace the three components at the same time - rear cogs, chain and chainset. But from researching this topic widely I read that if the new chain isn't slipping then there is no need to change the chainset? Here is a photo of the teeth on the chainset. Do you think I should ride it and if only change the chainset if the chain slips? Would certainly save me a lot of hassle as I am having trouble finding a set...
Jac

Will check out the video turorials.
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#8
Hi Jac;

Chain lube: I use Tri-Flo, which is a thin oil in a solvent carrier. The solvent evaporates leaving a thin layer of lubricant. Truthfully, any thin oil is fine. Bicycle chains are not tough lubricant challenges. Wipe down the chain with a clean old rag until clean, then apply oil to the whole length chain, spin the cranks a few times, and go up and down through all the gears (easiest on a stand - I use a bike rack on the back of our Jeep). Then wipe the chain again with a different clean rag.

Wheel, headset and bottom bracket bearings probably need to be regreased on your bike. I use boat trailer wheel bearing grease. It is in expensive, and resists the environment. I'd suggest doing this once a year at least. More often if you ride on the beach and get into the water.

My rule of thumb for saddle height as measured from the crank centerline along the seat tube to the top side of the saddle is 2" (5cm) less than your trouser inseam measurement. This is on the high side for some people, but works well for me. I like my saddle level. I like my handle bars an inch (2.5cm) lower than my saddle (flat bars); still working that out for drop bars. There is TON of personal preference/comfort in this....

Tires: most of my bikes currently have Kenda tires; but I am debating on trying some Schwalbe tires. They are about 2X the cost of Kendas.

The vast majority of my riding is commuting on paved roads and trails. Very infrequently on gravel paths, and never completely off road.
Nigel
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