tubesocksFred

I haven't touch my old road bikes for ages, mainly due to only having tubular wheels, and I did not feel like patching any of the 20 or so tubular tires I had that were punctured. I recently got one running because I had one running tubular tire and used the front wheel of a road bike I recently got. All I had to do was spray lube on the chain and loosen the few links that stiffened up. What I noticed is that on the Regina CX/CXS 7 speed freewheel, the chain would not stay on the 4th gear. It keeps trying and failing to hop up to the next gear. The chain looks like like it is a sedisport with its flared inner plates. I don't think there were 6 speed sedisport chains that were incompatible with 7 speed freewheels. I am wondering what the cause of the skipping is.

I could continue riding w/o the skipping gear since is the 16 on a 13-14-15-16-17-19-21 freewheel and I can ride on 15 or 17.

Here is a picture of the chain on the gear that is skipping. There is practically no clearance between the chain and cogs:




Here is the chain on a non-skipping gear, with a slight clearance between the chain and cog:




The freewheel itself, it seems the distance between 3rd and 4th gear are slightly narrower than others:




And the Regina CX 7spd vs 6spd. 7spd is wider:




I don't think there were a Regina CX 8 speed freewheel where a narrower spacer can be used, although the black spacer seems suspect.

davester

Sure looks like that black spacer is narrower than the others, which would explain the problem. Perhaps someone who didn't know what they were doing assembled the freewheel. The obvious solutions toe me are 1) buy another freewheel; 2) measure the pin width of the chain with some calipers and then buy a narrower chain (I would think that a 9-speed chain would work.

3alarmer 

...the cheapest and easiest fix, assuming you don't have the wherewithal to disassemble a Regina freewheel and a supply of spacers for that model, would be to buy a ten dollar KMC X plate 8.93 chain, shorten it to the correct length, and put it on your bicycle. I've used Sedisport chains, back when they were cheap, and the KMC X series shifts as well or better.

verktyg 

The original Sedisport chains were made for 5-6 speed FWs.

The second generation Sedisport chains were slightly narrower.

Here's a list of common bicycle chain widths. These chains are crude mass produced products not precision instruments so YMWV!

Multi speed chains, from 5 to 8 speeds have inner width of 3/32? (2.38 mm).
Multi speed chains from 9 to 12 speeds have inner width of 11/128? (2.18 mm).

Outside width of the links:

5 & 6 speed – 7.8 mm (5/16 in) (all brands)
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)
9 speed – 6.6 to 6.8 mm (1/4 to 9/32 in) (all brands)
10 speed - 6.2 mm (1/4 in) (Shimano, Campy), 5.88 mm (7/32 in) (Campy, KMC)

SRAM 6-7-8 speed chains, also KMC brand are going to be narrower than the Sedisport and will work better with your FWs.

You give up some strength going to narrower 9 or 10 speed chains because the links are thinner.

verktyg

pastorbobnlnh 

I agree with verktyg and 3alarmer that you need to replace the chain. I've found that a 9 speed KMC or SRAM chain shifts smoothly on my narrow spaced 6 speed and 7 speed freewheels.

There's a good chance someone removed the sprockets for cleaning and there was a shim with the black spacer that was either missed when reassembling or placed in a different position. While it is difficult to be certain from your pictures, the gap between the largest and second largest sprocket looks a bit wide.

repechage

And it’s Regina, things happen.

tubesocksFred

I see all the cogs type are correct, and according to this image, the black 'spacer' is not a spacer at all, but the only ring that is the body of the freewheel itself (between cog B6 and A2):






My measured spacing of the cogs (including the cog itself is around 5mm, with the exception of B6 to A2, which is around 4.5-4.7mm), with the cog being around 2mm, that means the gap is probably around 3.6mm, too narrow for those chains that are 7.5mm width. These are all visual measurement by eye, since I haven't seen my caliper in ages. Unless I got 2 K4 spacers in place of one, I don't know how that gap between B6 and A2 could be smaller (then the space between A1 and B6 would be bigger by 0.8mm). All these measurements are just done by eyeing it, since I haven't seen my calipers in ages.


I did measure the chain's link width and it is around 7.5mm (I had another Sedisport chain on another road bike frame and it measures roughly the same).


It is strange how it is skipping that gear, since that 13-21 freewheel was on my training wheel, and the 12-17 was on my racing wheel, and I must have been riding with it regularly (the bikes has been stored away for so long, I don't even know what I did with them, and I don't even know where my front training wheel is. My race frame's top/down tube is bent in, maybe that's got something to do with it).


Are the new 9-12 spd chain's inner spacing going to be too narrow? Given the cog's width is roughly in the 2mm range, and 2.18mm inner spacing of the narrow chains is cutting it pretty tight. Or maybe just go with KMC 8 spd chain.


I got all the tools to take it apart, but I would spend more time on it than I will be riding the bike.

repechage

It’s a Regina, manufacturing mayhem.

madpogue 

^^^^^ Maybe a vendredi apres-midi apres-dejeunet-de-merlot build. If the Sedisport is still good, I would roll it up for assignment to some future build, throw on a narrower modern-ish chain, and ride on. Like a bizarre gardening accident, it may be one of those mysteries best left unsolved......

Lazyass

Is it just me or is that dropout bent inwards? The axle nut doesn't look totally flush.

tubesocksFred

Its not bent, its just proximity of the camera to the freewheel, causing the side of the subject to flare outward.

Kabuki12

I have had issues with chains a couple of times . Once, I had purchased too narrow of chain and it seemed to slip between shifts and that sucked. Another time just a grinding feeling under load, like acceleration or climbing. Both times I replaced the chain with the KMC brand (can't remember which one but under $35) and problem solved. I am not sure if that is your problem, but FW and chain compatibility are very important even if it sets up well on the stand it doesn't mean it will perform under load.

tubesocksFred

As far as I remember, I was riding/racing with this setup until I stopped riding it decades ago and it just got left behind in my parent's garage. I can't remember the exact reason for this setup, but from reading the forums, Sedisport was the go to chain for all racers, same with the Regina CX/CX-S freewheel. So I must just have the standard racer's setup (using the 12/17 for flat race courses, 13/21 for training/hill race courses, Ambrosia rims for training, Campy rims for racing).

Charles Wahl

I started my "nice bike" life with a Suntour Ultra-7 FW (7 cogs with 126 OLD) turned by a Sedisport chain. Shifted flawlessly and made no undue noise. When the chain seemed a bit worn, and I got tired of trying to clean the chain without removing from frame or else driving out a pin to free it, I replaced it with a SRAM 870 with removable link. It shifted fine but always had a slight "hitch" on only one cog (in the middle -- my "cruising" cog) that didn't make noise but could be felt pedaling. The sensation bugged me so much that I replaced the (perfectly good) Suntour Ultra-7 with a standard New Winner Pro 6-cog; and the "hitch" disappeared. Rather than getting a new chain, I'd replace that freewheel. And eventually replace the chain. I've never mic'd the width of these chains, but maybe I should.

3alarmer 

...Sedisport was the go to chain for a couple of reasons. The first was that it was either the earliest, or one of the earliest returns to bushingless design, so it shifted very well, compared to the older style chains, with pins and bushings, driven into side plates. There is an illustration here, on the Sheldon Brown website, of the two sorts, compared. The KMC chain I recommended to you is also a bushingless design, just a little narrower overall, and recommended for anything from 6-8 speed cogs (but will also do OK on 5 cog setups).

The second is that they were ridiculously cheap, when purchased in bulk rolls. Which was how I got them. KMC X8.93 is also pretty cheap, when bought in bulk.

They seem to work for everything I own and ride, with one exception of a 9 speed rear on a bike I bought in a weak moment, not thinking clearly about what I enjoy.


Anyway, I hope you get it sorted out. Freewheels are not cheap any more, at least not the better quality ones. Chains, thankfully, still are, if you avoid some of the pricier narrow ones for 9, 10, 11 rear setups, and take a look at what's available. Certainly save your Sedisport, if not worn out, because for some reason they are expensive to buy used nowadays, even though they were cheap when new.