peweuk

Hi,
As I mentioned in the title I am new to biking. At my late years in life I have not had a bike since I was 12 when I used one to ride to school.
Now 50 years later I have 'retired' with time on my hands and recently acquired an old Raleigh from my father's shed when he died recently. He had not used the bike for a few years, and the bike I believe is about 15 years old - but still in good enough condition for me to use as a means of excercise. Here it is:




I know the bike is not worth anything in terms of resale and I cannot afford to spend a lot on it (retirement income being what it is), but I would like to continue using it for sentimental reasons.

I have had it out a few times and it rides well enough EXCEPT for one problem.

The rear derailleur is a 7 speed Shimano Altus




and this is the problem area.

There is a 3 Gear front mechanism, and whatever front gear I use, the rear mechanism always seems to miss gear 2 (ie the second smallest cog) when I change up.

Changing down is not a problem as all 7 gears engage.
Changing up from 1 - 2 has no effect, and cog 2 engages only when I set the gear lever to 3. The cogs are then engaged out of step by 1 until I change up to 7 - at which point 6 engages briefly then jumps to 7.

I find this difficult to understand as the rear derailleur appears to move position correctly through all 7 gears, it is just that the chain does not move correctly from 1 -2.
(NOTE: If I change down to 3, then back up to 7 the chain moves between the cogs as it should).

So assuming I have explained it well enough, if anyone has any idea what may be the cause of the problem, or what I should investigate further to try and identify the problem, I appreciate hearing.

Thanks

cny-bikeman

First, there is nothing at all wrong, unsuitable or inadequate about that bike. It looks to be in pretty good condition and it's not a cheap dept. store model.

Secondly, with the array of symptoms you mention there are many variables to diagnose correctly. Shift cable initial tension does need adjustment, due to the lack of shifting in the first click of the lever, but cable/housing friction, derailleur alignment, chain side wear, and lever problems could all possibly play a part. Although I would encourage you to learn about routine maintenance, and I know you are on a budget, I would strongly recommend you have a bike shop do an initial tune-up on it to give you a good starting point, address any safety issues, and avoid future problems, as you can't learn everything at once. It would be great if they could give you guidance afterward as to tire inflation, lubrication, and how to do a quick safety check on your bike before riding.

If you are determined to work on this particular problem you need to learn how to check the cable to see that it is running freely through the housing, how to adjust the derailleur limit screws, and how to adjust cable tension. If you do all of that, whether you are successful or not, I would still recommend taking it to a shop.

dsbrantjr

There are two common sources for such a problem; the cable is mis-adjusted or there is excess friction in the system. Here is a procedure for doing the adjustment: https://www.parktool.com/blog/repair-...nts-derailleur You may only need to perform the indexing adjustment part of the procedure since it sounds like you may be pretty close to having it working correctly. Making the adjustments will likely solve the problem.

If you cannot get it going using the above procedure a likely culprit is cable friction. When a bike sits idle for a long time the cables can rust and the lubricant hardens up. You may be able to clean and lubricate the shift cable; pay special attention to the lower loop of cable going into the rear derailleur. Dribbling a little light oil into the cable housings may be helpful and will not do any harm. They are also fairly inexpensive to replace.

peweuk

Gee, thanks guys - such quick responses.

You both 'seem' to have hit it right on the nail.

After posting I went out to the garage to 'experiment', as we have very strong wind and rain here at the moment and taking the bike out is not very appealing.

I had read some info on setting the stops and checking chain length etc, and on checking found that everything appeared to be in order - EXCEPT it did 'seem' that the cable was a little 'slack' in my limited experience, so I undid the cable at the derailleur end, pulled it through and re-tightened it.
This appears to have done the trick as far as I can tell in the workshop when I test with the bike rear wheel raised off the floor - but I will know further when the weather settles and I can get the bike out on the road.

So as I say, you both seem to have got it right, I'll let you know.

cny-bikeman - I may take up your suggestion and have a bike shop have a look at it and see what they advise.

They may suggest a new chain and sprocket set as these look a little worn - or are they supposed to look like this



Thanks again Guys

DiabloScott

The tooth profile on your cassette looks OK. You should be able to clean it off and use it fine - maybe spray some lube on there after. Replacing the chain would probably be well-spent money.

cny-bikeman

One can't really determine wear by looking at the cogs unless it's extreme. If it does not skip under pressure you're OK for now. You can check for chain wear yourself with a good ruler. Note that I always measure with the chain under tension, as I think it's more accurate that way. That is also the way chain guages work.

Shift to the largest rear cog and then lean the bike against a wall or bench, drive side out (p.s. all photos are best drive side out). Put the right crank level, pointing forward and put some pressure on it with your right hand - you can use an assistant if desired. Lay the ruler on top of the chain so that the measurement lines are against the chain (upside down if necessary) and measure a 12" span, starting and ending on the right side of a rivet. If you have longer than a foot ruler or a tape measure go from 1" mark to the 13" (or any other difference of 12." Rather than a lot of typing I'll refer you to Sheldon Brown's page on chains to interpret the results, as that way you have the opportunity to learn more about chains and maintenance and get an introduction to Sheldon's site as well: https://sheldonbrown.com/chains.html. Both Sheldon's site and Parktool.com are great resources. I've found the easiest way to find info on those sites is a simple Google search - sheldon chain or park tool chain, for example.

xenologer

A lack of shifting responce in the small cogs; i have noted to be common with this style of derailer.
The issue is that the parralelogram isnt sweeping the conicle profile of the cassette very well -in the small cogs the cage is vertically more distant from the cogs than in the large ones; thus overshifing is required to push the chain across them.
This is primarially a design issue; nicer/newer derailers have the parralelogram pivots angled upwards so the cage maintains a more constant distance to the cassette as it travels.

My usual solution to this, is to pull the b-tension all the way out; this will improve shifting responce at the cost of more noise in the biggest gear.
-your derailer looks to lack a b-tension adjuster

When b-tension is absent, I've also had luck in griding down the positioning nub on the derailer mount; thus having it mount rotated slightly forward and closer to the cassette.
-this isnt going to work here, as your derailer uses a 'claw' style mount

If it was me, and I was on a budget, then this derailer would be an upgrade:
https://www.amazon.com/Shimano-Tourne...ef=pd_sim_sg_2
there are nicer ones, but with careful tuning this can be made to shift well.

cny-bikeman

I believe the OP already found out the problem was cable tension, but that derailleur already sits much farther forward than the typical derailleur.

peweuk

Thanks to all for the additional input.

So if I decide to go for a new derailleur such as the Tourney suggested by xenologer, how will this affect the chain required.
I will check the number of links in the current chain, but I have seen 114 link and 116 link chains suggested for example for the Altus derailleur, how do I determine what I need for the Tourney?

EDIT: It's OK, I found the answer on ParkTools.

Thanks again.

peweuk

OK - so I'm back.

Since I last posted I have had the bike out quite a lot, and in the main it rides well.

After tightening the gear cable the gears worked well most of the time, but still missed the second cog on occasions - until I found a reference to adjusting the derailleur barrel adjuster. Once I adjusted the tension in the way it was shown on a video the missing went away completely.

However, I now have a second problem which is that the chain sometimes slips off completely when I change gears (almost always when changing from a larger to a smaller cog - and not always on 6-7, sometimes when going from 4-5 or 5-6).

I spoke to a local bike shop who said that they would have to see the bike to diagnose (fair enough) but at a cost of £30 + VAT, to cover 1/2 hour labour, within which time any parts replaced would be extra. Over 1/2hour add £30.
Thats more than the bike is worth, and their parts prices were also way over the top.
Unfortunately they are the only bike workshop within an hours drive of me, so it's back to self diagnosis and repair.

I could replace the chain (clarks), derailleur (Shimano TX55 6 / 7-speed) and cable (clarks) for £6, £9 and £2 respectively - add a further £9 for a new cassette (shimano tourney 7 speed screw on) - a total of £17 or £26.

But my question is -
is there one part that would be most likely to cause the problem in the gear change which sometimes sounds clunky, sometimes is silent and sometimes causes the chain to slip off completely when changing down.

Bill Kapaun

Go back to the Park website and peruse Limit Screw adjustments.

cny-bikeman

You did not mention the unshipping problem before, so I am with Bill - check the outer limit adjustment, as the most logical explanation is that you caused a new problem during your adjustment. However, it makes no sense that the chain would come off when shifting to an intermidiate cog, rather than the smallest, unless you are referring to it coming off in the front, rather than ther rear.

As for other causes, we don't know how worn the chain is, as you have not indicated you checked it for wear per the procedure I posted above, and side wear in an older chain can produce shifting problems. We also cannot tell remotely if there are unusual problems with the rear derailleur. So It's not possible to tell which of those could be a problem. In addition if it is unshipping in the front there is a new set of possibiliites. Not knowing the wear on the chain also means it is unknown if you will find problems meshing with the rear cogs if you change the chain. The cable is not causing unshipping but could cause inconsistent shifting if not lubricated properly or binding for some other reason. As I agree the labor prices are high (£60 or $92 per hour!) and it's a long drive to boot this is what I suggest:

1. Measure the chain for wear as I described earlier and refer to the link to Sheldon's site for interpreting the results.
2. Lubricate the cables where they pass through housing. Easiest way is to shift to the largest rear cog and then, without pedaling, shift the lever back to the opposite end, which will leave the cable very slack. At that point you should be able to remove the housing by using a slot that is in the downtube or chainstay housing stop - will look similar to the pic below. Once you have done that you will be able slide the housings enough on the cables to access and inspect the portion hidden by the cables. If there is any rust, broken cable strands or kinked cable/housing replace the cables and housing, preferably with stainless cables. You will need to Google replace bicycle shift cable and study several videos and tutorials so that you understand the entire procedure. If the cables look good, just feed some oil onto each section as you slide the housing back over it and the end back into the stop. Once you are done and the housing is in place turn the cranks and shift back and forth to make sure everything is seated. Always lube non-stainless cables, using a medium heavy oil - not grease.
3. Once you have addressed the chain and cables, recheck the limit adjustments and tension. If you are still having problems let us know everything you did and remaining symptoms.

peweuk

Thanks again guys.

Sorry I should have mentioned that after my last posting I:

- I checked the chain for stretch - using the steel rule method - none noticeable
- I lubricated the chain
- I adjusted the limit stops to prevent the derailluer guiding the chain off the cassette

Prior to that, as I mentioned previously, I had adjusted the cable tension by pulling through the clamp and then latterly using the barrel adjuster - and at the same time I did put some lube on the cable.

I will however re-visit all of these and the instructions/info you have so kindly posted and double check everthying is in order (as far as I can tell).

cny - I was a bit puzzled about the chain coming off whilst changing through intermediate cogs as I could not find any references to that as a problem anywhere that I have visited for info.
I don't think it is a front derailleur problem as I have it set on the mid cog (2 out of 3) and have so far never changed it.
Some times when the chain drops out it comes off the back only, and on the odd occasion comes of both.

Anyway, as I say, I'll re-visit all the above and see what the outcome is.

Thanks again.

Bill Kapaun

It might be a matter of a VERY slight turn of the limit screw. Something like 1/4-1/2 turn.
IF you go too far in, you simply won't reach that cog/ring. It's really a no harm-no foul. Going out too far is NOT desired.

Also, don't use the screws to "jack" the DER over. When adjusting the screw for a large ring/cog, have the chain on a smaller ring/cog & vice versa.