Preamble
If you already have a freewheel hub with a 7 speed freewheel gears (i.e. MF-TZ07) using an IG or HG (hyperglide) chain, this chain will only work for 6,7 or 8 speed gear sets. Any higher and the chain will not sit correctly on the narrower pitched gears… see Bicycle chain – width:
- 6 speed – 7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)
- 7 speed – 7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)
- 8 speed – 7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)
…
Shimano uses the same chain types on 6, 7,and 8 speed designs.
So if you need to switch wheels to one using a cassette, and you want to retain the existing chain, then you will need a HG gear cassette, as a CNXXXX will not fit the chain. So a Shimano CS-HG20 7-Speed Cassette (13-23T) would do the job. Note that a spacer may also be required.
Also ensure that the hub/cassette is hyperglide (or compatible).
See also
The meat
on ebay
- Shimano CS-HG20 7-Speed Cassette, £1+£3.20
- Vintage Shimano Hyperglide 7 Speed Cassette 13-23, £10+£3.20
It is possible to get higher than 28T toothed gears, such as the (probably cloned) Shimano CS-HG200-7 Speed Mountain Bike Bicycle Cassette 12-28T or 12-32T New,£10.95
Note that a spacer may also be required for some cassette hubs that are designed for 8 speed cassettes, such as the Shimano SPACER 8/9-speed to 7-speed Cassette, which looks rather plastic
I had two different spacers from the collection of hubs that I purchased, see below. One 1 mm and one 2 mm:
[photo]
This spacer is placed behind the cassette, that is to say that it goes on to the free hub first… see 7-speed MTB cassette on 8/9-speed wheel hub, where does spacer go?
Specs
I have a 559 wheel with 36 spokes, 45 mm diameter hub (spoke to spoke).
Shopping around BKK for a quality freewheel hub
Tired of the cheap Chinese freewheel hubs, with their easily busted bearings and cones, I went down to Worachak looking for a quality (freewheel) hub in order to minimise the pain of changing to a cassette based gear. I could get a cheap Cinese wheel for 280 baht, from United cycle.
The first quality shop, Cycle Sport, @Cyclesport-TH on Line, had a front and rear wheel set for 2800 baht, they would not sell a rear wheel on it’s own, it had to be a set. Formula hub, Alexrim RM19 rim and Pilar spokes (Pilar are Taiwanese apparently. The quality brands start with DT Swiss at the top, then Satim and then Pilar, apparently, according to the guy in the shop. The front and rear hubs on their own were 650 baht (together, I think)
The second quality shop was across the road, Sport Work. There the Formula hub was 600 and 400 for rear and front respectively (they were available in silver or black). It is unclear whether they were the same. Black anodised spokes cost 100 baht more than the silver spokes. Rear wheel alone was 1900 baht and front 1700 baht (the difference being the 200 baht for the hubs). Together 3600 baht, no discount.
Note that Sport Work and Cycle Sport are in fact the same shop/owners, so it is unclear why the difference in price. Maybe the hubs were different. However, this disparity in price alone put me off
There was a cheaper shop next door to Sport Work, as can be seen it the photo above, which is called SpeedBike, but they wanted 450 baht for the same cheap Chinese wheel as the first shop, so thanks but no thanks!
The cheap shop run by the three old ladies wanted 380 baht ( it was 250 a couple of years ago) for a cheap Chinese wheel
I ended up getting the 280 baht wheel from United Cycles, the very first shop.
Purchases on eBay
I already had two rear cassette hubs, that I had bought as a set of three for ~£14:
- FH-HG50, and
- FH-HG20
along with a front hub, an Exage HB-RM50.
The FH-HG50 luckily had a lock ring included, but the FH-HG20 did not. Two quick release levers were also included. The bearings were fine for the two rear hubs, but the front hub’s bearings required replacing.
The front hub is quite stiff and gritty and will probably need dismantling and re-greasing and maybe new bearings (and cones?). In Pracha Songkro, at the bike shop next to Hwai Kwang market, I was quoted 120 baht for each side of the hub, so 240 baht in total. I’m sure that I could do it cheaper myself, see Reballing a Shimano HB-RM50.
I had also purchased a brand new 7 speed cassette, CS-HG41-7ac, for around £0.99 (?), which came with a lock ring and two spacer rings (1(?) and 2(?) mm).
When the cassette was placed upon either hub, without the spacers, and the lock ring tightened by hand, it seemed like there was a little bit of play and that a spacer would be required (between the 7th and 6th gears there appeared to be a 1-2 mm gap)
FH-HG50 with CS-HG41-7ac
FH-HG50 with CS-HG41-7ac
FH-HG20 with CS-HG41-7ac
FH-HG20 with CS-HG41-7ac
Note that the FH-HG50 has a scored, “threaded” end to the splines, whereas the FH-HG20 does not.
Getting the hubs swapped
A tale in itself… Friday: On the way to get the wheel hub swapped a motorcycle crashed into my and buckled the front wheel. Hopefully that can be fixed by spoke re-tightening. The the boy in the shop didn’t understand what I wanted, but seemed to imply that the hubs can’t be swapped. I was told to return on Monday to see the english speaking old lady
Monday: I went back with the front wheel to get it straightened, and enquired as to the rear wheel hub swap. The old lady said the same, that the hubs can not be swapped. However, it isn’t clear why. Is it because:
- Its a ploy to get me to buy a wheel
- They just don’t want to do it, or
- The hubs are actually different, and the offset would be different and would require new spokes..?
What ever the answer, it must be possible. It might be a good idea to invest in a cheap Chinese rear wheel for 280 baht and just try to swap the hubs myself and then get them balanced later. I was thinking of getting a new wheel anyway as it is less likely to have a buckled rim.
See on StackExchange
Costs of a hybrid solution
Buying a cheap Chinese wheel and swapping the hubs for a better quality… is it worth it? If you already have an old wheel and a spare hub (or can purchase a second hand hub for less than £5, then certainly. But what about buying a new Chinese wheel and new Formula hubs? How does that stack up against having a quality wheel made for 2800 baht? Let’s do the sums…
- Chinese wheel 2 x 280 = 560 baht
- Formula hubs (freewheel rear and front) 650 baht
- Spokes – the spokes from the cheap Chinese wheel can be reused.
- Labour 2 x 160 = 320 baht
- Total = ~1500 baht
So a saving of 1000 – 1300 baht and you still have low quality rim and spokes… Hmmm… not as cheap as one would like…
gr33nonline 