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Discussion Starter · #1 ·
So, I finally got rid of the crappy stock 1-piece triple front cranks (HEAVY, steel?) and replaced them with a new-ish set of Truvativ FireX cranks with just the middle ring remaining. It had a couple of bent teeth, but they got 'straightened' in a bench vice before installation and I thought it'd work fine on a SS, but..........

I took that half-completed ghetto SS project bike around the yard last night and it is skipping when I mash on it hard. I assume the problem is with the front ring, but can't really tell. The chainling looks straight. Any ideas?

Oh, its a 32x16 and I'm using a Nashbar tensioner (push DOWN only) and a new PC-1 chain.
 

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Discussion Starter · #3 ·
I have the chain as tight as I can without the possible use of a half link. How do those work exactly? Is it a single link that has on male end and one female end?

Sorry for the dumb questions. This is my first attempt at a build.
 

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upstatesspdr said:
I think it is more likely skipping on the rear cog.
Those push down type tensioners are not the most effective but they do work ok.
Shorten the chain as much as possible and they work better.
when selecting the chain length do so WITHOUT the tensioner in the equation. get it as close as possible (short as possible) and THEN route it through the tensioner...

these cheapos do work just fine, but, require a bit more TLC on the install. if you still cant get it 'just right' then you may need to look at buying a half link.
 

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Discussion Starter · #6 ·
nogearshere said:
when selecting the chain length do so WITHOUT the tensioner in the equation. get it as close as possible (short as possible) and THEN route it through the tensioner...

these cheapos do work just fine, but, require a bit more TLC on the install. if you still cant get it 'just right' then you may need to look at buying a half link.
I did that. I zip tied the tensioner up against the bottom of the frame while removing links, then cut them to allow the tensioner to swing down into place. It pushes down far enough that the top and bottom of the chain are almost parallel now. I'd like to try and get a better 'wrap' on the rear cog my using less chain if possible.

That used front chainring might be giving me trouble too. It's tough to say.
 

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Try and determine what position your crank arms, and thus the chainring, is in when the skip happens. Does it consistently happen in the same spot? If so, is it where you straightened the teeth? It might be the chainring or the chainring and chainline. Put a bit of White Out on the rear cog and see if it happens in the same spot on the rear, too (I'm betting it won't) just to double check it isn't the rear. I bet it's a combination of the bad teeth on the chainring and a slight chainline misalignment. Check your chainline with a straight edge to make sure it's good. Finally, make sure you don't have a stiff link in the chain. This is probably not the cause, as a stiff link should cause skip at all times, not just under load.

If you have a spare chainring I'd just replace the battered ring and see if it fixes the problem.
 

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The usual suspect..

hallin222 said:
I did that. I zip tied the tensioner up against the bottom of the frame while removing links, then cut them to allow the tensioner to swing down into place. It pushes down far enough that the top and bottom of the chain are almost parallel now. I'd like to try and get a better 'wrap' on the rear cog my using less chain if possible.

That used front chainring might be giving me trouble too. It's tough to say.
The usual suspect is your tensioner. If you use a spring type tensioner then, if the chain skips without the tensioner, it can skip with one. Take the spring, throw in your misc. parts bend. Now convert your tensioner into "push up mode" by rolling the chain over the top of the pully and use a zip tie around the chain stay to hold it in place; viola' a push up mode tensioner that can not slip. Either that or use a derailleur ala Keith Bontrager in the FAQ.

1G1G, Brad
 

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Discussion Starter · #9 ·
aka brad said:
The usual suspect is your tensioner. If you use a spring type tensioner then, if the chain skips without the tensioner, it can skip with one. Take the spring, throw in your misc. parts bend. Now convert your tensioner into "push up mode" by rolling the chain over the top of the pully and use a zip tie around the chain stay to hold it in place; viola' a push up mode tensioner that can not slip. Either that or use a derailleur ala Keith Bontrager in the FAQ.

1G1G, Brad
I tried that really quick, even before I reaad this post. It seemed to work better on my 1 minute test ride. I hadn't taken out the spring yet, but I will. Next time when I build a higher quality bike, I'll make sure to buy a push-up unit to begin with.

Thanks folks.
 

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Go with a SS frame..

hallin222 said:
I tried that really quick, even before I reaad this post. It seemed to work better on my 1 minute test ride. I hadn't taken out the spring yet, but I will. Next time when I build a higher quality bike, I'll make sure to buy a push-up unit to begin with.

Thanks folks.
SS is so mainstream now you shouldn't have to build a "higher quality bike" without horizontal dropouts or an EBB. Regardless, even if I used a quality "push up" tensioner I would throw on a zip-tie. I noticed at the Sea Otter, a couple of the front runners were using tensioners and they all had zip-ties; just carry a few extras and a knife in case of a flat :p .

1G1G, Brad
 

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hallin222 said:
So, I finally got rid of the crappy stock 1-piece triple front cranks (HEAVY, steel?) and replaced them with a new-ish set of Truvativ FireX cranks with just the middle ring remaining. It had a couple of bent teeth, but they got 'straightened' in a bench vice before installation and I thought it'd work fine on a SS, but..........

I took that half-completed ghetto SS project bike around the yard last night and it is skipping when I mash on it hard. I assume the problem is with the front ring, but can't really tell. The chainling looks straight. Any ideas?

Oh, its a 32x16 and I'm using a Nashbar tensioner (push DOWN only) and a new PC-1 chain.
I have the same tensioner and got the same results with 32x16, its the tensioner. I was able to "magic ratio" with a half link and the skipping went away. That tensioner was more trouble than it was worth, I was constantly dropping the chain with it also. Use a ziptie to put it in push "up" mode or get a Rennan or try a magic ratio.
 

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Discussion Starter · #12 ·
I've got it zip tied up right now and it seems to be working ok. I had a half link to try, but brought home the wrong size (width). I'll get the proper size next week. I may try dropping one tooth on the rear cog to attampt a majoc ratio. But, this is my first SS, and I don't want to make it TOO hard to pedal. :)

I got a rear brake on tonight so the bike is operational. Its pretty simple. Just what I was going for. A front brake will probably be added later.

Pics to come tomorrow, hopefully.

Ian
 
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