Sekai-Wheelset

[gageplate]

I just found this site and looks like everybody is very helpful. Sooo, I am in the process of rebuilding an old Sekai bike with my 14 year old son. We are watching lots of videos and learning as we go but i am now completely confused on wheels. The rims i have say 27x1 1/4. Can anybody tell me the tire size i would need. He is trying to convert the bike from a ten speed to a single speed. Is there a site that will sell a decent priced wheelset for a freewheel single speed and am i only tied into a 27x1 1/4 wheelset (can i buy a different size without tweaking brakes? Still trying to get the cassette off. I believe from watching videos that i need a specific cassette remover. Any and all responses would be much appreciated. Thanks all.

[Painkiller]

lets some close up pics of your freewheel and we can help you with the right tool. as far as the tires for your rims any tire from 27 x 1 1/8 to 1 3/8
would be nice. here is an example at a great price
http://www.nashbar.com/bikes/ProductDisplay?storeId=10053&langId=-1&catalogId=10052&productId=207850&utm_source=Google_Product_Search&utm_medium=pla&utm_campaign=datafeed&cm_mmc=Google_Product_Search-_-PLA-_-Datafeed-_-Vittoria%20Zafirro%2027-inch%20Road%20Tire%20%2027X1%201/8&Quot;&CAWELAID=1011819165&catargetid=1572651379&cagpspn=pla
if your wheels are in good shape stick with the 27in. .I run the 27x1 1/8 on mine but you may want wider if you are going to slam it around a bit. You can probably spin a single speed freewheel on the hub you have once you get the old freewheel off. get your new single speed crankset and correct bottom bracket for your new chainline and should be good to go. then you will not have to mod the brake set up.
Nigel may chime in and correct me where i may be wrong on rear gear swap so when he does listen to his advice, he has experience with that type of metrics. But I wanted to get the ball rolling
another critical thing for this mod would would be chain length and tension,
so again some pics of your dropout area too

[gageplate]

thank you painkiller. I will click some pics and send them out. This is new to me so if i use the wrong terminology i apologize. When we bought the bike, the person also tossed me a single speed cassette. I am assuming that once i get the old cassette off i would just screw the new cassette on. Once that is on, how does it stay in place. I understand it screws on but will it slip around? Not sure if that makes sense. I will put some pics on the site for you to see. Again thanks alot.

[gageplate]

Okay here is the cassette. I hope you can see what i need. Also, this is the cog (?) that was given to me. Once screwed on, is that all i have to do?Hope i did the pictures right.
[attachment=3583]
[attachment=3582]

[1FJEF]

That is a Freewheel you are trying to remove as opposed to a Cassette. It requires a specific tool. If you are going to make it a fixie or singlespeed it's a moot point.
That cog (freewheel, it makes a ratcheting sound when you coast) you wish to install is really made for a different hub. It will look goofy as it will be in line with where the biggest cog on the factory freewheel is now.
Please get an accurate measurement of the distance between the two rear drop outs (how wide it is where the rear hub fits in, in millimeters)
Like this

You need to know this to buy a new rear wheel. I suspect you'll find it to be 126mm. One can often squeeze a 130mm into 126mm drop outs.
I personally would prefer to see if the brakes can be adjusted to allow switching to a 700c wheel. Brake shoes need to move 4mm lower, so look for 4-6mm of play.
Show pictures of the brakes if you want our opinion.
Please post a side view picture of the rear drop outs (the slots that the wheel mounts in). You may need a chain tensioner when you switch to singlespeed.
Here is a full (inexpensive) SS wheelset for you. He will help you make it fit. He also has them in 27inch & 700c
27inch (630mm)


700C (622mm)

[gageplate]

first let me say thanks for all the helpful responses. 1F thanks for all the info and pics. The distance is 126 between the drop and yes they are horizontal. I have disassembled the brake but if i remember, it did seem like they could move down a bit. Not sure about 4mm will have to check. If i were to use that freewheel cog, besides it looking funny, would i have t add spacers or something to keep it in place? I was planning on taking apart the front cogs and just using the smaller one up front. Would that work for the wheel you are showing me to buy or now do i have to change the front set up as well. Thanks again. Hope you don't mind the questions.

[nfmisso]

(10-09-2012, 08:52 AM)gageplate Wrote:  ...... If i were to use that freewheel cog, besides it looking funny, would i have t add spacers or something to keep it in place? I was planning on taking apart the front cogs and just using the smaller one up front. .....

Getting some spacers would be good, so that you can get the chainline (line up the front and rear cogs) aligned.

You can also play around with the side to side location of the chainring on the crank, and put some washers there also (you need M10 stainless steel shims: http://www.mcmaster.com/#standard-metric-shims/=jnb6uv )

You need one of these to remove your current freewheel (it is not a cassette):
http://www.amazon.com/Park-Tool-Freewheel-Remover-Freewheels/dp/B001B6RGYU/ref=sr_1_1?s=cycling&ie=UTF8&qid=1349801750&sr=1-1&keywords=suntour+freewheel

I would keep the present wheels for now.

I would strongly recommend that you replace the brakes with modern dual pivot side pulls - I like Tektro.

Ask questions

[gageplate]

Nigel Thank you very much. Got the cassette off (not to hard) and now have the freewheel on the hub. Bike is being painted so i am not sure about this but i am hearing that my chain line will be way off. This may need to move to a different forum but thought i would ask. If the line is off, what now? Do i buy a new (shorter BB) or can i shim the freewheel out a bit, which would shorten how much the freewheel is actually threaded on. Any thought/insight would be great. Thanks again.

[nfmisso]

You can shim the freewheel out a bit - as I suggested above.

In addition, you can shim the chainring inwards using M10 washers (as suggested above).