Hi all, I’m a covid stat having purchased a bike during lockdown. Had been toying for a while as we live on the trans pennine trail, and have previously enjoyed exercise bike in the scarce use of any gym I’ve been in.

I SHOULD ADD, THAT I KNOW NOTHING ABOUT BIKES. I AM LITERALLY LEARNING AS I GO.

I’m based in the UK and I have acquired a second hand Whyte 605 (2015) and having not ridden a bike prior to this, for what, 20 years… decided to get it serviced (the rear brake was spongey). Which led to further expenditure on this and that. This and that being;

– New brake pads front and back (Stock, Tektro Auriga)
– Bleed front & back
– Headset bearings replaced
– New Cassette (Shimano HG400)
– HG Chain

This is the first ‘fully serviceable’ bike I’ve ridden/owned, so have no idea what’s what, or what a good ride should feel like. Anyway, the bike was serviced and had a new cassette and chain. Now upon riding hard in gears 15-18 I’m finding the chain is occasionally slipping when peddling ‘hard’.

Speaking to the LBS, they’ve suggested it probably wants a new set of chainrings, or it was suggested a new 1x crank, on the basis that I said I never shift my front gears from the second set.

I actually rode the father in laws Orange P7 Pro the other day and noticed he only had a single front ring. So assume this is common with keen cyclists (of which, I am not).

Anyway.

As far as I can tell, I have the following set up;

– New Shimano HG400 11-34T Cassette & Relevant HG chain.

On ageing/original (5 year old);

– SHIMANO Acera FC-M391 9 speed MTB Bike Crankset 44-32-22T.

What options do I have in terms of fixing this occasional slip? And what should I look at if I was to go single ring? I’ve already spent way more on this bike than I ever dreamed of, replacing the crank for a single ring seems to be another sizeable expenditure I had not planned for.

I have read it is possible to do a 3x to 1x on the cheap, by simply buying a new middle ring, and disconnecting the shifter etc… If I was to consider this option, what products should I be looking at? I’ve seen talk of wider chainrings and shorter bolts etc? There’s also discussion of Gear ratios, which completely went over my head!

Forgive my ignorance in any terminology, I am 100% cycle-retarded.

Update:

Upon closer inspection, from what I can gather, I have;

Shimano M391 9 speed (175mm) Chainset
104bcd Chainring
Shimano BB-UN26 Square Taper (68mm Bottom Bracket)
44/32/22t Cassette

On the basis (I assume) my middle ring is 32T, are my options simply;

1. Replace existing 104bcd chainrings. Given I only use the middle, I could be cheap and only replace the middle chainring…? (Considering a Race Face 32T, would that be a like for like of my middle chain ring? and suitable?)

OR

2. Whilst still trying to be cheap, I could replace my chainset, for a single one. I would assume I would need a new bottom bracket (to replace the existing Shimano 68mm square taper), so had seen something like a 68/73 SRAM DUB bottom bracket and then get an SRAM DUB X1 single crank… which seems the cheapest way? Is there anything else I’m missing? Bolts? Caps?

Are these assumptions;

– accurate?
– suitable?

I look forward to your educating replies 🙂

I guess another option, is simply stick with a 3x Square Taper chainset, and continue to only use the middle ring, replacing like for like.

A new M391 is ~£35, which is the same price as the single middle chainring I was looking at…

I’d say just replace the worn chainring for now or if your replacing the chainset as recommended above, which can sometimes be cheaper ( still find this a bit mad) be sure to check that it is suitable for your bottom bracket axle length.

Different chainsets have different offsets hence the various lengths of bottom bracket available to keep the correct chainline. You can find this info on manufacturers sites as it’s not always displayed on retail sites.

Don’t be into much of a rush to get dragged into upgrading to the latest and greatest too soon. You’ve just started, it’s an entry level bike and your more likely to upgrade to a nicer bike later on if you get into as much as us mugs!

All best and enjoy.

Pic of chainring please.

First of all, thanks for your reply. Your response is kind of where my head was going. Spending £150+ on a new chainset, would mean I’ve spent more on maintenance/parts than I did in the first place on the damned thing.

Secondly… I see these options;

1. Buy (import) an entirely new M391 Chainset, costing £35. The benefits being, its like for like so a straight swap and gives me 3 new chainrings as well as fresh looking cranks.

2. Buy the Race Face (or similar, recommendations welcome) 32T chainring, and just go with this. Ignoring the 44/22 that are probably just as worn!

3. Buy a cheap like for like Shimano chainring to replace the middle chainring, £10-15.

4. Buy a second hand Race Face/Hope 32T for £10-15. (Suspect, with 2nd hand, could face the same issues?)

Whats the deal with Narrow/Wide chainring, am I safe to assuming my Chain is set up for that, or is that infact the norm?

Also, what is an offset, on a chainring?

I suspect you may want wider angle pics of the offending chainring, but these are all I have to hand, and they show the actual chain on the chainring itself, so probably hiding some of what you wanted to see 😀

Assuming this isn’t some sort of elaborate troll…

Is that photo of the cassette before it was replaced because that looks like 7sp? NB, the cassette is the set of gears on the back hub.

Above, are all pics of the front hub?!

Apart from this below, which is the cassette;

Difficult to tell from the pics.
Try looking at the chain whilst applying pressure to the pedals, with the rear brake on. Watch to see if the chain is moving outwardly away from the chainring, i.e. what it’d do if that is what is causing it so slip.
Other possible kind of slip-ish cause is a stiff chain link, but that only tends to fell odd every 4 pedals rotations or so. To look for a stiff chain link watch how the chain goes around the jockey wheels slowly.
Basically study the drivetrain to see if you can work out what is causing the slip. 🙂

That’s a different cassette to the one you posted above it… ?

The second photo is definitely the cassette. Chainrings look pretty worn to me.

You’ve got pics of ‘front hub’ and ‘rear hub’ now. It could be my wording perhaps?

I thought the cassette was the rear, which I had replaced 2 weeks ago, and a new chain fitted. And now I have chain slip. LBS has suggested the issue is most likely because the ‘front hub’ (chainrings??) are too worn to keep up with the new chain and cassette?

Plausible? Feasible? Sensible?

So… I’m exploring avenues of ‘fixing up’ the front hub.

Upon inspection, second photo IS cassette. My bad. The top two pics are old, taken on the day I got the bike. You all have eager eyes.

Ignore second photo 🙂

Ignore the ironing board on the back.

If the problem is slipping in gears 15-18 (chain on middle chain ring at the front, and on the smallest and right-most sprockets at the back) then you could just shift the front to the big chain ring and see if that solves it.

This is not an elegant solution, but it’s the cheapest and it might tide you over until it all beds in, or until you know more about what you need. In general, try to avoid combining (big at front) with (big at back), and vice versa, because these combinations are kind of pointless and they stop the chain running in a straight line.

I’d forget the 1x idea on cost ground tbh. You haven’t got a clutch mech which you really need to help retain the chain, and you don’t have a wide range cassette (although you might not need one if you get by just with the middle ring now).

I’d either get all 3 new rings at the front, or if you really don’t use / don’t want to use the small and big rings at the front and can replace just the middle one with a suitable shimano ring then do that.

Good point @drdjpower, Ive been meaning to try that.

Chainrings don’t look worn.

If any of them was, it would cause slipping in all gears.

You need a new bike shop.

If it was my money I’d go for a new middle ring. It’s used most, certainly off road where it’s also most exposed to being ground away by dirt so they tend to wear before the other two. You might want to see if the slipping occurs in the other two rings first though, if it does the new crankset will be cheaper than 3 rings probably.

Not 1x, they have a different type of cassette with a massive 1st gear, you’d want that if you loose the small chain ring.

I’d take the option to shift into the big front chainring and if the slipping stops, swap the middle chainring like-for-like. The rings are only about £10-15 –

https://www.ebay.co.uk/itm/Shimano-Chainring-FC-M532-Deore-32-teeth-9-speed-silver-PCD-104mm-/313041688142

The only problem is you need a special tool to remove the bolts holding the chainring in place – it’s a normal 5mm allen key on one side and an annoying two pronged tool thing on the other. You’d also have to, as a minimum, take the pedal off the crank arm to replace the rings (which ideally requires a pedal spanner, a normal 15mm spanner might not play nicely), and possibly even remove the crank from the bike which requires another special tool. By the time you add up the ring and the two or three tools you’d be better off taking it to the bike shop and paying their labour costs and RRP on the chainring.

It seems strange to me that it only slips in two sprockets on the cassette – that suggests to me that there’s something wrong with the set up, not that the chainring is worn. That may be as simple as tweaking the gear cable tension but it’s almost impossible to tell over the internet. Try the big front chainring and if that works you can go from there.

Thinking about cynic-al and now monrobiker’s posts, they make a good point.

Maybe check your B screw adjustment. You’ll have to look on YouTube for that one, it’s too hard to explain in text!

Thanks all, I’d read about b-screw adjustment, but dont really like to tinker. I guess I just need to try and remember how it was before tinkering.

Theres a few things for me to try here, before spending £, which is good.

– Try in different front ring
– Check B-Screw

I’ve been looking at like for like chainsets, to make life some what easier and cheaper. Finding a like for like of my existing FC-M391 seems to be tricky. It seems to be a bit of a rocking horse turd, probably given its age. Whilst you can still seemingly import them, they tend to either have different ring sizes 48-36-26T as opposed to my 44-32-22T, or shorter crank arms 170mm as opposed to my current 175mm — is the difference in arm length that noticeable?! What about the different chainring sizes? I guess if I deviate from my current size, I’m looking at issues with my chain length etc?

Whilst hunting, I noticed an FC-M371, there was one just ended on ebay which was exact like for like. Just as I was about to bid, I noticed the M371 appears to be riveted as opposed to replaceable. So withheld.

I now have my eyes on a FC-T3010, which is a “trekking chainset” apparently. Specwise, it seems to match my existing FC-M391, in that it is 44/32/22 w/ 175mm. The only difference I can see is that it appears to have a protective cover over the chainset. Would that be accurate?

My level of competency with anything mechanical, is unscrew, replace like for like, and screw back. So I’m keen to get like for like.

Upon inspection I found this (no idea what the technical term is) –> https://www.youtube.com/watch?v=1kMKIP61t1A

I seem to have resolved the above by unscrewing the B slightly, which seems to have moved the derailleur closer to the cassette? I just need to get out and test.

Very good! That was what I meant by adjusting the B screw. It controls the distance between the top jockey wheel, (small ‘cog’ on the derailleur arm) and the cassette sprockets. If you move it too close you’ll have a problem getting onto the largest sprocket but at the other end if its too far away, the chain doesn’t wrap around enough teeth and it will skip.

Glad you got it sorted and at no extra cost. 👍

Very good! That was what I meant by adjusting the B screw. It controls the distance between the top jockey wheel, (small ‘cog’ on the derailleur arm) and the cassette sprockets. If you move it too close you’ll have a problem getting onto the largest sprocket but at the other end if its too far away, the chain doesn’t wrap around enough teeth and it will skip.

Glad you got it sorted and at no extra cost. 👍

Just had a short 20km ride, changing the gears is much smoother in 2×5-9 which were previously clunky. And it didn’t skip this time.

Though I found myself in lower range due to the wind in which I was peddling in to 😀

Will keep an eye on it of course, but seems much better.