stephr1

Hi all,

I was here a while back concerning issues about replacing my 7-speed cassette. I did do the replacement, tho not as I hoped I'd be able to Anyway.......

I've been riding on the new gears and have been experiencing what feels like chain slip (feel it in the pedals) on the cassette, specifically when I am climbing (not very steep uphills, tho).

It seems to be only in top (7th) gear, which is 11T. I checked (and readjusted) the derailleur and found that the top gear limit stop screw was out of adjustment. Thought that'd take care of it, but did not. I'm planning to pull the cassette and see if the slippage is being caused by some issue (like the 11T gear slipping because it's not well seated on the hub?) between the cassette/gear 7 and the freehub...which brings up my question....

My bike is a 1999 Specialized Hardrock. It has what appears to be a Shimano Compact freehub (slightly different outside end design than other hubs) which is supposed to allow it to work with 11T top gears. The cassette I put on is a low end CS-HG30-7, 11-28 (had a CSHG-60-7). The chain was replaced, as well (SRAM PC-870, 8-speed).

I thought this cassette would work with my hub. Am I wrong? Any suggestions or things I might look at?

Thanks in advance....Steph

KevinF

Chain slip usually means that the chain isn't meshing with the gears. The chain was replaced; is the cassette brand new as well?

What you're describing sounds like a worn-down 11t cog not meshing with a new chain.

I've also seen some weird issues happening when the cassette lockring isn't fully torqued down.

stephr1

Yes, both cassette and chain are brand new. A few years back I replaced only the chain and ended up with lots of slippage, but in the top 2-3 gears (and ended up replacing the cassette). So, I get what you're saying about new meshed with old.

You suggestion about the lock ring not being torqued enough was on my mind as well. I thought I tightened it down enough...maybe not. That was my thought behind pulling the cassette to see if there are any unwanted scrapes or marks on the freehub. I was wondering if anyone had any other suggested possibilities that I hadn't thought of.

I'll post back what I find.

Thanks for the help.

Cheers...Steph

Andrew R Stewart 

Make sure the chain is fully seating in the cog valleys. Sometimes the wrong spacers or lockring will keep the chain from engaging the teeth to a full depth.
Tight links, twisted links, connector link/pin not fully set.
The smaller the cog the more the need to have all right.
Try another chain.

Why are you climbing in such a high gear any way, and maybe in a crossover one at that? Andy.

LarDasse74

I beleive there is a specific lockring you need to use with the 11 tooth cog. The regular lockring interferes with the chain.

Papa Ado

Not to do with the slippage, but the HG cassette is meant to be used with a chain that has 7.3mm pins.

PC870 has 7.1mm pins.

Anyway - back to the slippage problem...

stephr1

Thanks to all for the inputs.

I have not yet taken the cassette off. However, it looks like the chain is seating OK (visually, anyways).

I'm using the lock ring that came with the new cassette. I do still have the old IG-60 cassette so I may see if that lock ring makes any difference. The spacer issue was also something that crossed my mind, but not very seriously. I also used the spacers that came with the new cassette. I'll pull out the old cassette and compare spacing between the new and old and see if/where there are any differences and make any adjustments.

When I installed the IG-60 (the one recently replaced by the HG-30) a few years ago, I had no problems at all with it (same gearing, 11-28, as this new HG-30).

One correction: In an earlier posting, I stated that I had replaced the chain and then replaced the cassette because of slippage. That's actually the other way around. I replaced the cassette first, then realized I needed a new chain

As mentioned previously, I'll post back what I find. Should get to the bike in the next day or so.

Thanks again and cheers...Steph

stephr1

OK, so I got around to looking at the rear gearing. Nothing seemed disproportionately out of whack (there's so much "slop" in these older bikes anyways). I compared the new cassette to my old cassette and while there were differences between the 2 cassettes in how the spacing was done for the 6th and 7th gears (relative to each gear), it all seemed to match up just fine.

I checked to see if there was any slippage of the 7th gear on the freehub, and neither the gears nor the freehub showed any signs of metal stripping or fatigue (I thought there might be some odd spacing issue and the 7th gear wasn't seating down onto the freehub causing a problem). So, it seems the gears are remaining in place just fine.

There were 2 things I did notice, but I'm not sure how much impact they might have. First is that while the main cassette body (1st 5 gears are riveted together) sits (mostly) firmly onto the freehub, the 6th and 7th gears seem to have a bit more play when installed. Like I say above, tho, I saw no evidence the gears were slipping. The 2nd is that if I spin my rear wheel fairly fast (opposite direction of engaging the freehub cog), I notice a very slight "wobble" between the wheel/wheel hub and the cassette. It would seem that I may have a slightly bent axle. It appears that the more serious part of this slight wobble is down by the lower gears which means by the time the wobble gets to the upper gears, it doesn't seem to have much effect.

Good news is no serious problems found (other than I prob'ly should replace the axle). Bad news is I have no idea what's causing the slippage when I "stand on it" in 7th gear. It could very well be some off-the-wall compatibility issue between the chain and cassette. I reinstalled the cassette and hit the lock nut with a reasonable amount of torque (w/out over-tightening it, tho). I'm doing a short ride tomorrow, so I'll see if maybe I just happened to solve my problem.

I'm still open to hearing any ideas anyone might have about this.

Thanks and cheers....Steph

Mondo734

I had a similar problem not too long ago. In my case it turned out that the freehub had gotten gunked up and at first would only slip when I was on the 11t cog. As I continued to ride on the next cog and on others up hill it slowly started to slip on those as well but that took time before it started happening. What I did was pull the freehub off and take it apart as best I could and flushed it with mineral spirits. After it dried I relubed it and it has worked fine since.

stephr1

I did my short ride today and the slip is still there going over a bridge in 7th gear (have not experienced any slips in other gears). However, I can't seem to duplicate the problem in the garage. Must need the added stressing out on a ride.

Thanks for your experience on the freehub. I had been wondering about this as a possibility. I have maintained the FH by keeping it reasonably lubed (w/Tri-Flo), but have never cleaned it with solvent. Now I wonder if dirt has somehow made its way inside. interesting that I'm only having problems in 7th gear like you did at first. Maybe my next step is to remove the FH and do a thorough degreasing/relubing. I also am going to recount ball bearings. A few fell onto a rag underneath the wheel when I regreased the hub during replacement of the cassette/chain. I thought I got them all (They seemed to fill up the bearing area). Maybe I fooled myself

I also noticed that the dust cover on the inside near the outside edge of the FH is loose. I tried to remove it and couldn't figure out how, so I put it back in place as best I can, but it still seems a bit loose. Any thoughts on this, or is this insignificant in the bigger picture?

I have to own up here that I have 18K+ miles on the bike. So I'm also pondering if the FH is just worn out. Tho, it's a bit confusing since I didn't see this problem until I replaced the chain/cassette. And the old stuff wasn't "that" worn out (i.e. minor shifting problems, but no slipping). Maybe this is like the chain/cassette connection. No slips with the old stuff, but replace only the cassette or the chain and unexpected problems appear.

You mention mineral spirits....any other suggestions for degreasing the FH? I had a thought of using WD40, but am concerned about leftover WD40 breaking down the new lube.

Thanks and again and cheers....Steph

stephr1

Thanks for that piece of tech info. I guess the good news is that the dimensions are not switched which might cause the chain to ride a bit high in the groove...certainly a possible source of slippage. However, I'm about to do a closer visual and physical look-see to determine if this is truly chain slippage, or possibly related to the 18K+ miles I have on the freehub....

stephr1

I appreciate your suggestions. This is becoming one those obvious problems with a not so obvious solution

When I bought the IG-60 cassette a few years back, it came in a Shimano box with docs. This time, the HG-30 came in a plastic bag...actually 2 bags. A small bag held the 6th and 7th gears and the lockring, so I'd like to believe I got the right lock ring for this cassette. That was in a larger bag with the main cassette (gears 1-5 riveted together). I want to believe this was mfg'd by Shimano (lock ring says so), but the bag had no printing and I don't remember anything other than the no. of teeth stamped onto the cogs (one of the cogs may have had the CS-HG-30 model number stamped on it). I bought it thru Walmart and suspect this was a qty. buy from Shimano and was packaged this way to shave a few dollars off Walmart's cost.

I did compare the new lock ring with the one from the cassette I replaced (which never gave me any slip issues), and they look pretty much the same...maybe exactly. I could try using the old lock ring and see what happens, but I suspect that may not make a difference. I am going to go back over the whole hub/freehub/cassette/chain assembly (again!! and see if I can determine how well the chain is seating in 7th gear. I also want to figure out the source of the slight "wobble" I noticed and see if that might not be a/the main contributing cause.

Cheers...Steph

stephr1

Hey Andy,

Thanks for the thoughts.

I'm fairly certainly the chain is seating correctly, however, I plan to do a more thorough check in the next day or so. As I mention above, I believe the lock ring is pretty much the same as I had on the cassette I just replaced, but I'm going to take a closer look at that. I'm not sure how much of an impact this might have on slippage, but I need to go back and see if I removed enough links from the chain. Fairly certain I did, but I'll double check that, all the same.

I typically ride paved trails (have semi-knobby tires that can ride street). The hills I climb are typically bridges I cross and had no problem doing that with the old cassette. I'm on the middle chain ring and typically start in 3rd gear and spend most of my time in 7th.

Cheers...Steph

stephr1

So I had a chance to go back thru things. Turns out I had all the hub bearings in (thought it possible I might have lost one along the way I took off the new cassette and saw there was a bit of wear and tear where both the 7th gear and freehub engage with each other. Had not seen that before (I think I commented earlier that when I first put on the new cassette all the gears felt a bit sloppy on the freehub).

I then took another look at the old cassette and compared it to the new one and realized the old one wasn't in that bad of shape at all...I would guess at least 1k or more miles left on it (My original reason for the new cassette and chain was because of shifting problems and I thought the cassette was worn out and should be replaced along with the chain). After thinking the new cassette might be ruining the freehub, I cleaned up the old cassette and reinstalled it. I then had what I never had with it...what could be called chain skip even worse than with the new cassette

I still wasn't convinced that somehow the Hyper-C freehub wasn't holding onto 7th gear. I was able to eliminate that idea by marking tops of two adjacent gear peaks (?) on 6th and 7th gear. I figured if 7trh gear slip was the problem, the marks on the 6th and 7th gears would be away from each other after a skip or 2. Tested this a few times and the gear peaks always remained in place. So much for a problem with 7th gear on a Hyper-C freehub.

So, I now know one thing it's not. I don't want to believe it's chain skip (especially with a new cassette), but I can't rule that out yet...at least, not until I can prove otherwise. Although, I used grease as my markers to determine 7th gear slip and while I could tell 6th and 7th gears hadn't slipped relative to each other, I could also see that the grease I put on a 7th gear peak appeared undisturbed (I would expect the chain to have wiped across the top of a gear peak if the chain skipped)....which would tell me the chain wasn't skipping at all (a few assumptions go along with this).

A couple of thoughts and here is where I would appreciate feedback.

Of course, it's hard to specifically determine chain skip when you're riding the bike (at least, not without becoming a hazard to myself 8)...only that something of that nature is going on. If I assume for the moment it is chain skip in 7th gear, is it possible the derailleur may have lost some of its tensioning ability (weakened or broken spring...tho I've looked that)? I would have expected the problem to also show up in 6th and maybe 5th gear. From my inexact testing, the derailleur feels OK. Is this a common problem?

The other thought (and someone mentioned it above) is the possibility I've got a freehub that's at end of life (both the rear derailleur and freehub are original which means they have 18K+ miles on them). I heard some odd noises when I spun the rear wheel right after putting on the new cassette (also made me think I left out a ball bearing). Before putting back on the old cassette, I did a degrease of the freehub and then oiled it up with Tri-Flo. Most of the odd noises went away, but the freehub still feels just a wee bit "hinky" when I turn it (tho I can't make it skip by hand).

So, I'm tempted to buy a new freehub, but I wanted to hear from some folks before I do.

Thanks in advance and cheers....Steph

stephr1

PROBLEM SOLVED!!!! If anyone is familiar with "Occam's Razor", the simplest solution is usually the right one, then my situation fits right in.

After doing a stress test on my freehub (and finding it to be in solid shape), I noticed something about the chain. It turns out that in some sections of the chain, the diameter of the bearings that go between the links (and over the pins) was much less than the distance across the outside edge of the link at that point.

What that means is that in some places, the chain (bearing, actually) was not fully seating into the gear (critically important on an 11T gear) and thus I had chain skip. I put back on my old chain and, voila', the skipping went away. I'll use it until I get another new chain (which means I have to deal with minor shifting issues until then). I don't know if SRAM has changed the specs for this particular chain, but the quality certainly sucks. The new chain is a PC-870 that I bought because SRAM says it's a replacement/upgrade for a PC-58, the old chain. Hmmmm...I wonder.....

Tomorrow I head over to the LBS to make an exchange (Not a normally stocked item, unfortunately). Sheeesh!!!!

Thanks to everyone for their help. Looks like I can get back into my riding routine.

Cheers and safe riding...Steph