tomireland Posted October 21, 2014 Report Share Posted October 21, 2014 Hi, folks I recently bought a second-hand Onza T-Bird as just starting out. I noticed that the back hub has got 2 sprockets on it, but they're on either side of the hub, left and right side, in between the hub and the chainstay. Is it normal to have a second one as I've never seen this before? One sprocket looks slightly larger, so I assume it's to flip the wheel around to run a smaller rear sprocket. Just never seen it before. Cheers! Tom Quote Link to comment Share on other sites More sharing options...
tomireland Posted October 21, 2014 Author Report Share Posted October 21, 2014 In addition, it would appear that the side where the chain is, it's an 18T rear freewheel. Other side is just a screw on 12T sprocket. Quote Link to comment Share on other sites More sharing options...
woahroger Posted October 21, 2014 Report Share Posted October 21, 2014 I believe it's so that it can double as a "fixie", or a trials bike. Quote Link to comment Share on other sites More sharing options...
isitafox Posted October 21, 2014 Report Share Posted October 21, 2014 I'd assume the previous owner bought the wheel 2nd hand and it had the 12t on which he couldn't remove so he left it on and just put the FW on the other side. There was quite a few hub with both sides threaded like you say to be able to flip the wheel and run 2 different gear ratios. The 12t is because the most common gearing on a 20" is an 18t FFW on the cranks and a 12t rear sprocket. Quote Link to comment Share on other sites More sharing options...
Earl Posted October 22, 2014 Report Share Posted October 22, 2014 (edited) Hi, folks I recently bought a second-hand Onza T-Bird as just starting out. I noticed that the back hub has got 2 sprockets on it, but they're on either side of the hub, left and right side, in between the hub and the chainstay. Is it normal to have a second one as I've never seen this before? One sprocket looks slightly larger, so I assume it's to flip the wheel around to run a smaller rear sprocket. Just never seen it before. Cheers! Tom It’s called a flip flop hub old style thing it’s from the time when front freewheels was just starting out. it’s so if you did not have the tools like a vice to remove your rear freewheel you just take the wheel out turn it round put the 12t on and put wheel back in change cranks put chain on and done your now front freewheel In addition, it would appear that the side where the chain is, it's an 18T rear freewheel. Other side is just a screw on 12T sprocket. Normal gearing for 20" bikes rear 18t rear freewheel crank 22t rear 12t crank 18t front freewheel Edited October 22, 2014 by Earl Quote Link to comment Share on other sites More sharing options...
lifes-a-trial Posted October 22, 2014 Report Share Posted October 22, 2014 mainly for front free wheel set ups so you can have two differant gear ratios with fixed sprockets on the hub. Quote Link to comment Share on other sites More sharing options...
tomireland Posted October 23, 2014 Author Report Share Posted October 23, 2014 Thanks for all the replies, that helps clear it up. 22-18 (rear freewheel) appears to be my setup. Just wondering if freewheel could be moved to the front and then I can use the 12-T fixed sprocket. So it'd be an 18-12 setup with FFW. Not sure if that'll work though, so appreciate any thoughts. Cheers! Quote Link to comment Share on other sites More sharing options...
waybe2014 Posted October 23, 2014 Report Share Posted October 23, 2014 22:18 will be really light as mods either run 24:16 or 18:12 but most free wheels are 18t Quote Link to comment Share on other sites More sharing options...
tomireland Posted October 23, 2014 Author Report Share Posted October 23, 2014 22:18 will be really light as mods either run 24:16 or 18:12 but most free wheels are 18t You're telling me! It's like pedalling into air. So do you reckon the 18T freewheel on the rear could be moved to the front? As mentioned I have a fixed 12T on the opposite side, so could potentially flip the wheel and have an 18:12 setup, but not sure if it's do-able or not. As you can tell, I'm vastly experienced. Quote Link to comment Share on other sites More sharing options...
waybe2014 Posted October 23, 2014 Report Share Posted October 23, 2014 Moving the free wheel from rear to front shouldn't be a problem if you are running a bash plate. You will need a free wheel removal tool and a crank puller although I have never done it myself. If you have a bash ring there may be compatibility issues Quote Link to comment Share on other sites More sharing options...
tomireland Posted October 23, 2014 Author Report Share Posted October 23, 2014 Cool, thanks @waybe2014 . I have a bash plate and also have a bash ring, so there may be an issue there. I'd need to take a closer look though. Cheers for the advice! Quote Link to comment Share on other sites More sharing options...
isitafox Posted October 23, 2014 Report Share Posted October 23, 2014 I'm going to make an assumption that if you have a 22t sprocket on the front then you have normal 4/5 bolt style cranks. To fit the freewheel on the front you would need a set of threaded cranks to screw it onto. Quote Link to comment Share on other sites More sharing options...
waybe2014 Posted October 23, 2014 Report Share Posted October 23, 2014 Sorry completely forgot about that Quote Link to comment Share on other sites More sharing options...
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