Help restoring Polygon bike

[oldjc]

Greetings Folks,

This is my first post, so correct me if I get out of line.

I'm not a bike mechanic by any means but I am pretty handy, and I'm in the process of migrating the parts of a Polygon Cascade 2 hardtail to a new frame. The original frame was damaged by a hit and run.

I'm pretty sure I'll need to get the tool to take apart the chain, and now I think I may need to replace the rear derailleur (but that's another thread). So I've got everything off the old frame except the chain and crankset.

Before I dig into the crankset and possibly do more harm than good, is there any advise you can offer? If you could direct me to a how-to video for this particular model that would be great. This might help: WHEELTOP TCSH2-CFPG 42/34/24T 170 MM. I've looked at several how-to's and don't really know which one, if any, applies to me.

Thanks for bothering to read this and for any help you can offer.

 

[DCBassman]

!
Tools, you will need some specific tools to remove cranks. I'd invest in a basic toolkit, I got mine from Decathlon. Rather than look for someone dismantling your exact model, have a look at the Park Tools videos on YouTube. They do a good job of explaining things.

 

[T4tomo]

almost certainly a square taper crankset, so you need a square taper crank pulling tool, like a park tools ccp-22.

you can get cheaper copies and ones that use a spanner/ wrench rather than having a built in handle.

View: https://www.youtube.com/watch?v=cPQyQnNdews&t=52s


you simply remove the dust cover off the non drive side crank, attach the tool and wind the crank off.

you may also then need to remove the bottom bracket and refit it to the new frame, avian just watch the relevant park tool video.

 

[oldjc]

almost certainly a square taper crankset, so you need a square taper crank pulling tool, like a park tools ccp-22.

you can get cheaper copies and ones that use a spanner/ wrench rather than having a built in handle.

View: https://www.youtube.com/watch?v=cPQyQnNdews&t=52s


you simply remove the dust cover off the non drive side crank, attach the tool and wind the crank off.

you may also then need to remove the bottom bracket and refit it to the new frame, avian just watch the relevant park tool video.

Yes, this is the type of crank set I'm dealing with. Got a hold of the tool needed for the bottom bracket as well (The local bike shop loaned it to me [I edited this in as an afterthought, thinking you might get a kick out of it]), but the drive side wouldn't come off. I'm thinking it was damaged when the car hit me, so I've ordered the part.

Making progress. Thanks guys.

 

[ChrisEyles]

Sometimes the bottom bracket can be quite difficult to remove from the frame.

Remember that the right hand (drive side) cup is reverse threaded!

If you struggle to remove it, you can try clamping the removal tool vertically in a vice, fitting it into the BB cup, and then twisting the whole bike frame around to unscrew it.

I've used this method on a few stuck cups that wouldn't come out any other way, it's a good trick to have in the bag.

 

[ChrisEyles]

The Park Tools website linked above is an excellent resource for this sort of thing, as is Sheldon Browns website:

https://www.sheldonbrown.com/

Good luck with the build!

 

[oldjc]

If you struggle to remove it, you can try clamping the removal tool vertically in a vice, fitting it into the BB cup, and then twisting the whole bike frame around to unscrew it.

That's a great tip!

I"ve got the bike back together with a new frame, bottom bracket and rear derailleur. Learning as I go. I won't bore you with the details of having to take the chain apart and back together several times. I've taken the bike around town on errands but wouldn't trust it on a vigorous ride out of town.

Didn't notice until late that they sent me a rear wheel with an eight speed cassette rather than the original seven. Probably why the rear derailleur (Shimano Tourney RD-TY200) is a bit off. Guess I'll end up taking that chain apart at least one more time.

 

[ChrisEyles]

Well done, sounds like good progress.

The rear mech will be fine with an 8 speed cassette, you'll just need an 8 speed shifter to replace the original 7 speed one (fortunately available quite cheaply).

 

[oldjc]

Yeah Chris. I was thinking that or trying to replace the new cassette with the old one. But I imagine replacing the cassette would take more time and effort, since I would probably need the specialized tool/s. Plus the damaged old wheel has been out in the elements.

 

[ChrisEyles]

The 7 speed cluster of sprockets on your old wheel looks like it's a freewheel (ie pawls & bearings located inside the sprocket cluster, which then screws onto a threaded hub).

The new 8 speed one you have will be a cassette (ie slides onto a splined freehub on the wheel, with the pawls/ bearings located on the wheel freehub rather than inside the sprocket cluster).

They're not cross compatible I'm afraid - the good news is the cassette / freehub set up you now have is a better option than the older freewheel system.

If it were me, I'd get hold of an 8 speed shifter for the rear mech and keep everything else the same. That's probably going to be cheaper than buying a new 7 speed cassette (which are a bit niche, cassettes came in at around the same time as 8 speed so most cassettes are 8+ speed).

This also means you won't have to buy a chain whip and cassette removal tool (though these are great to have for long term maintenance and will save money in the long run vs going to a bike shop).

 

[ChrisEyles]

That's some pretty serious deformation of the wheel too - hope you escaped relatively unhurt!

 

[oldjc]

If it were me, I'd get hold of an 8 speed shifter for the rear mech and keep everything else the same. That's probably going to be cheaper than buying a new 7 speed cassette (which are a bit niche, cassettes came in at around the same time as 8 speed so most cassettes are 8+ speed).

Wait. It makes sense to get a shifter to match the 8 speed cassette, but wouldn't I also need to also get a matching derailleur? I think the current one has a 6 - 7 speed range.

I'm about to contact Polygon to let them know they sent me the wrong wheel. At this point I think the easiest thing would be to switch out the wheel.

 

[ChrisEyles]

The shifter is the important bit, 7/8/9 rear mechs for MTBs are all compatible with one another.

The only thing you need to check is what the maximum sprocket size your rear mech can accommodate is (this is usually a conservative estimate in the manufacturer's specs, so you're fine to exceed it by 2-4 teeth in my experience).

If your current mech will handle the largest sprocket on your 8 speed cassette, then all you need is an 8 speed shifter.

Personally I reckon that's the best way to go, as a like for like rear freewheel wheel is likely to be slightly lower end, since its pretty much obsolete now except on lower end bikes.

But if they're paying for the crash damage repair, either way's good!

 

[DCBassman]

wouldn't I also need to also get a matching derailleur? I think the current one has a 6 - 7 speed range.

I've used 7-speed mechs out to 9-speed with no problems, it'll be fine.

 

[oldjc]

OK, so I've ordered the 8 speed shifter and a set of cables. In the meantime I'll just putter around town with the gears that work for me.