Author Topic: Budget solutions for a tilting saddle  (Read 347 times)

Budget solutions for a tilting saddle
« on: November 02, 2019, 09:03:29 am »
I've become fettler-in-chief for some Norwegian students who are over here for 6 months.

They've managed to pick up a couple of secondhand bikes, one of which I spent a couple of hours on last week fixing brakes, plugging handlebars etc to make it safe.

It's a Carrera Valour (https://www.halfords.com/cycling/bikes/mountain-bikes/carrera-valour-womens-mountain-bike-s-m-l-frames), which is in pretty good nick structurally, but the saddle is persistently tilting to crazy angles. We're tightening the seatpost bolt as much as we dare, but it's not holding. I've not yet had a chance to take the clamp bit apart and inspect it to see what the situation is, but I may get a chance to tonight or later in the week.

Under other circumstances I'd be recommending they buy a two-bolt seat post, but given that they're only here for a limited amount of time and don't want to spend money on the bikes unnecessarily, are there any bodgy fixes we can try to keep the saddle horizontal?


quixoticgeek

  • Mostly Harmless
Re: Budget solutions for a tilting saddle
« Reply #1 on: November 02, 2019, 10:03:31 am »

Last time I had this happen, it was the ridges in the soft aluminium that had got worn down. The only solution I found was to just replace it.

Maybe put a 2 bolt on, run it for 6 months, swap back the original when you flog it, and keep the 2 bolt in stock?

If you were closer, I'd lend you one of those I have here spare (I bought the wrong length).

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Budget solutions for a tilting saddle
« Reply #2 on: November 02, 2019, 10:40:56 am »
Maybe try putting some (paper backed) sandpaper between the mating surfaces.

LittleWheelsandBig

  • Whimsy Rider
Re: Budget solutions for a tilting saddle
« Reply #3 on: November 02, 2019, 10:53:26 am »
Clean the mating surfaces of the seatpost clamp and put epoxy on them. Cheap and cheerful.
Wheel meet again, don't know where, don't know when...

Blodwyn Pig

  • what a nice chap
Re: Budget solutions for a tilting saddle
« Reply #4 on: November 02, 2019, 11:11:46 am »
Basically there are usually 2 common types of saddle clamp,
First is the 'snails back' type, which is notorious for slipping (tilting) as it appears to be one shiny surface sliding off the other shiny surface. 
Second type is the 'cupped hand type' which normally have serations on both mating surfaces.
If the former, then I have had some temporary success, by taking the clamp apart, then with a hack saw, make a series of scores across the surface, in all directions, on the 'hump' that is the top part of the post then with some very rough sandpaper, rub the inside of the upper section, to roughen it up.  This should provide a better grip, and when you use the allen key, use something over the end to extend it, and use one hand to push the allen key up into the bolt.

Alternatively any seat post with the cupped hand and serrations should work fine ( 27.2mm dia presumably). I'm sure if you put a wanted add, you could pick one up fr the price of postage.  Just make sure its long enough.

Re: Budget solutions for a tilting saddle
« Reply #5 on: November 02, 2019, 11:13:36 am »
I have some spares 27.2mm and 27mm if you can get down to Worcester. I could meet you somewhere maybe at Shrub Hill.

I've become fettler-in-chief for some Norwegian students who are over here for 6 months.

They've managed to pick up a couple of secondhand bikes, one of which I spent a couple of hours on last week fixing brakes, plugging handlebars etc to make it safe.

It's a Carrera Valour (https://www.halfords.com/cycling/bikes/mountain-bikes/carrera-valour-womens-mountain-bike-s-m-l-frames), which is in pretty good nick structurally, but the saddle is persistently tilting to crazy angles. We're tightening the seatpost bolt as much as we dare, but it's not holding. I've not yet had a chance to take the clamp bit apart and inspect it to see what the situation is, but I may get a chance to tonight or later in the week.

Under other circumstances I'd be recommending they buy a two-bolt seat post, but given that they're only here for a limited amount of time and don't want to spend money on the bikes unnecessarily, are there any bodgy fixes we can try to keep the saddle horizontal?
Most people tip-toe through life hoping the make it safely to death.
Home

Re: Budget solutions for a tilting saddle
« Reply #6 on: November 02, 2019, 11:14:06 am »
When I had this problem, I recut (or at least lightly enhanced) the grooves on both surfaces with a hacksaw or the corner of a file. Couple that with doing the bolt up a couple of grunts past bastard tight, or at any rate as bastard tight as you can get it worth a normal allen key, and it's been fine since.

I just know that if I tried epoxy, I wouldn't realise I'd got the angle wrong until the epoxy had cured.

PaulF

  • "World's Scariest Barman"
  • It's only impossible if you stop to think about it
Re: Budget solutions for a tilting saddle
« Reply #7 on: November 02, 2019, 12:03:38 pm »
What size do you need? May have something you could have for postage costs

Re: Budget solutions for a tilting saddle
« Reply #8 on: November 02, 2019, 12:11:08 pm »
swap back the original when you flog it

Ah yes, there is that approach too, I suppose!


RE abrasives, hacksaws and epoxy etc, I've grabbed a piece of inner tube I can give her to try. I'll ask them what their plans are for the bikes at the end of their stay and suss out what level of bodge might be acceptable!


The Halfords website says this is the spec for the seatpost: Carrera alloy, 31.6mm, 34.9mm seat clamp. I'd like to get some verniers on it too, though. Once I'm happy I know what size it is, I'll probably give it a go and try and source a secondhand post.

 
I have some spares 27.2mm and 27mm if you can get down to Worcester.

Thanks Hon, but I live in Lancaster now so that's less easy than it used to be!  ;D

What size do you need? May have something you could have for postage costs

Thanks! Tentatively a 31.6mm (see above)

Re: Budget solutions for a tilting saddle
« Reply #9 on: November 02, 2019, 12:59:44 pm »
I'm assuming that the seat pin is a single-bolt type here; another cheapo solution is to drill a small hole (through the top of the seat pin and the lower half of the clamp) and to fit a pin (old spoke?) through it, or a self-tapping screw.  You do this when the saddle is already in the right place of course, so it ought to be in the right place automatically. However if you mess up and it isn't, the lower part of the clamp assy can usually be turned and you can have another go at it.

However a common failure in cheap seat pins is that the lower clamp is steel and has bent and/or  split.  The clamp can be weld repaired, but any seat pin that has moved (and originally relied upon serrations) will be in trouble and will need something doing.

Another workable bodge is to mark the correct position of the clamp parts and then (with the lower half of the clamp only on the top of the seat pin) inspect the clearance between the end of the slot and the bolt.  It is sometimes possible to install some kind of spacer so that the clamp can't move.

FWIW the hole drilling method is usually the quickest and easiest.

cheers

Re: Budget solutions for a tilting saddle
« Reply #10 on: November 02, 2019, 01:12:15 pm »
^^^^ would be my first thought.

Is the thread stripped in the clamp? If so a longer bolt and a nut over the top of the clamp will work. I have a recycled 27.2 clamp that has this bodge (it's a two bolt one, the new arrangement is a PITA to tighten up but it works fine!)

PaulF

  • "World's Scariest Barman"
  • It's only impossible if you stop to think about it
Re: Budget solutions for a tilting saddle
« Reply #11 on: November 02, 2019, 01:15:28 pm »
Sorry mine are all 27.2 I’m afraid

Cudzoziemiec

  • Solar powered, tea fuelled cycle-wol
Re: Budget solutions for a tilting saddle
« Reply #12 on: November 02, 2019, 01:45:24 pm »
Solutions for a tilting saddle? Nikki? Okay, what's she making now? Maybe Wobbly John has input?  :D
A cup of tea is the perfect bridge between real life and cake.