Senseless upgrade or?
 

I have a few questions of which I could start a thread for all of them or just do it now. Just do it now!

Background: This all started with wearing out a rear block, more like a couple of sprockets in the block. This is on my commuter that now has over 3000 miles on the original block. Amazon is a friend with Prime so I ordered a replacement 7 speed block. Their supplier sent an 8 speed block. I checked the order and sure enough I had ordered..... a 7 speed block! I complained, they sent a replacement and I sent back the original. The replacement was the same that I sent back, an 8 speed block. I emailed Amazon explaining how incompetent their supplier was in reading the box description of the content. I suppose Shimano is to blame as well with one character in the PN being different, not! The responded with apologies (good), told me to keep the one sent, (OK) and the next day I got a 7 speed block.

Sounds good huh! Well not really, The tooth counts between the two 7 speed blocks are different and now my gearing is messed up such that I am limited in top speed with my cadence. At my age, I have some difficulty in increasing my cadence but really, I would like to kind of coast down hill while pedaling with minimum force without having to hit 110-120 cadence.

Since the 8 speed block tooth count progression looks better, I was thinking of converting to an 8 speed block in the rear. I purchased 8 speed shifters and made sure my RD was up to the increased range. As you know the free hub is shorter on the 7 speed than the 8 speed so I could just swap free hubs. I happen to have an XT rear hub for an 8 speed.

1. Should I swap the existing hubs or just the free hub?
Current hub:
[IMG]https://farm8.staticflickr.com/7536/...9cff48cc_b.jpgP1030871, on Flickr[/IMG]

Replacement hub:
[IMG]https://farm8.staticflickr.com/7335/...40bfa199_b.jpgP1030864, on Flickr[/IMG]

2. What model block is this? It is lighter than the new one, oh its the extra sprocket!
[IMG]https://farm8.staticflickr.com/7785/...be1757e5_b.jpgP1030867 on Flickr[/IMG]
[IMG]https://farm8.staticflickr.com/7215/...d922f5f9_b.jpgP1030869, on Flickr[/IMG]

8speed replacement:
[IMG]https://farm8.staticflickr.com/7480/...d713b35b_b.jpgP1030870, on Flickr[/IMG]

Oh, you say I should have posted this in the Bicycle Mechanics thread. The bike is almost C&V, 1997 RockHopper.

I feel like you should be able to just swap the freehub. You might have to play with spacers though. Pretty sure this can be done as long as the axle length is the same.

Replacing the freehub is a ten minute job at worst. Replacing the hub, for me, would take an hour or so. If the current hub is in good shape, I'd swap out the freehub, install the cassette and shifters, adjust the RD and cable tension, and call it a day. Not sure what you really gained here, though...is the smallest cog smaller than the former 7 speed?

[MENTION=170517]rccardr[/MENTION], any tips on removing a freehub if not mounted on a wheel (as pictured above?)

I'd swap the hubs rather than fart around with the freehub swap... or just build a new wheel, a CR-18 is pretty cheap and a good rim :) I've run into incompatible cones and dust seals when swapping freehubs but I can't speak to those specific models. It's not insurmountable but it can be annoying. You might also want to check to see if you'll need to adjust the wheel's dish after you change the spacers and stuff around.

You can drill a hole in a piece of wood and cut that in half to use as a clamp in a vice to hold the bare hub if you want to swap the freehubs.

Are your shifters indexed, or friction? Pretty sure the 7 and 8 speed cassettes would be compatible if you use friction (might have to adjust the stop screws on your RD). If you have indexed - either you need to switch to friction mode, get 8 speed shifters, or live with the new 7 speed cassette, or use the new 7 and get a chainring with a tooth or two more on it.

edit - why not remove the lockrings and move good cogs from the new one to the old one?

[MENTION=170517]rccardr[/MENTION] - The gain is the smallest sprocket, 12 on the new 7 and 11 on the new 8. The original had 11 too.
[MENTION=19743]USAZorro[/MENTION]w - Using index and have both 7 and 8 speed shifters. Swapping sprockets is a possibility too.

New 8 speed is: 11.13.15.17.20.23.26.30
New 7 speed is: 12.14.16.18.21.24.28
Old 7 speed is: 11.13.15.18.21.24.30

The current hub is in good condition. I have repacked it once already.

The option of building another wheel is good too. I wouldn't mind a slightly wider rim.

First, I find it hard to believe that swapping from an 11 to a 12 tooth cog causes all that much strife, but the legs want what they want. Components - Drive Train - Cassettes - 7 speed - Niagara Cycle <---- here is a link to a page with all sorts of 7 speed cassettes for sale, from a company that generally knows the difference between 7 speed and 8 speed. Any one of them listed with an 11 tooth small cog will get you back to where you want to be. Beware the one cassette on that page with a 10 tooth cog - I don't know if that would be compatible with any old hub/chain combo. Getting a minor change in gearing does not generally require disassembling hubs or building wheels.

The sun rhyno lite is pretty wide and a good value too... go for around 30$ on amazon and probably easy to order from an LBS.

That's over a 9% jump. Seems worth it to me if it's what you want/need.

If, once you get back from your smoke break, you have a chance to read the rest of the sentence, I said as much, then gave a link to a supplier of multiple cassettes with 11 tooth cogs.

Whatever. I read your whole post. If you are only putting the first part of the statement in so you can retract it a few words later, why leave it in at all? If it's there it's not unreasonable for a reader to assume you mean something by it. If I misconstrued your meaning and offended anyone, I apologize. And no, I don't smoke, whatever that's supposed to mean.

I agree that swapping the freehub should be pretty easy. I put a 4500-series Tiagra freehub on a Mountain LX rear hub for an '89 RockHopper, and it was pretty easy. As I recall, you might need to redish the wheel and use the cone and spacers from the donor hub.

Honestly, I would build a new wheel, but that's mostly because I like building wheels.

BTW, I have a front hub that matches your rear hub. It's been sitting on a shelf in my garage for years because I'm OCD about matching wheels and I haven't found the M750 rear at a decent price. If you would like to have it to pair with your, we can work out a trade. Alternatively, if you don't build a wheel with yours I'd be interested in acquiring whatever you don't use of it.

Good point about getting a freehub off of an unlaced hub. Guess you could use a compression wrench like a strap wrench, but it might damage the finish. So if you want a wider rim anyway, maybe lacing the 8 speed hub to a new wider rim is the ticket.

I took two 2x2's, stuck them in a vice and drilled a 1" hole between them. Stuck the hub in the hole and cinched down the vice util the 10mm wrench wouldn't turn the hub and broke it free. No damage to the hub. That's where I am at now. I need to take the wheel off to work on that hub.

Looks like I am going to swap the free hubs.
[MENTION=111144]Andy_K[/MENTION] I like matching hubs too but I would like the 8 speed better. When I get the either the Bottecchia or the Trek done, the RockHopper will likely end up being an off-roader. I have a suspension fork for it with an XT M755 hub laced to a Mavic X223 disk rim, so will save the M750 to go with it. I will try to let you know what settles out. Since I have a disk in front and Linears in the back, the rims won't match.

OK now I am confused about my goals! I am beginning to settle on two sets of wheels, one for off-roading and another for leasure with the differnece being tire tread, knobbies vs. smooth. Swapping out forks is a 20 min effort. In any case, I should have 8 speed on both to minimize the swapping.

Just installed the 8 speed free hub on the existing hub. Shifter replaced and adjusted close enough for fine tuning. Need to adjust the dish now.

Finally completed the install. What is a bit strange and caused me to ponder was the twist shifters for the 8 speed are numbered in the opposite direction from the originals, both Sram products. When did they switch over?

Shifts much better, distribution is better and I finally have a high gear I can use! Great upgrade.