Front Mech

[Jody]

Bit of a newbie question but its bugging me and want to be sure before I make the purchase. I didn't clean the bike properly before it went into hibernation and now the front mech has siezed.

Anyway, its a top pull for a triple chainset but my friend says its a bottom swing type and all I can find is top swing types. It looks like the type below.

Any idea what type is needed?

 

[I like Skol]

Not a clue, but why don't you un-seize the current one? It is unlikely to be that badly gone that it is scrap, chuck it in a bucket of old oil for a day or two then give it a forceful talking to. That should do the trick and save you some pennies and heartache.

 

[Yellow Saddle]

Top and bottom swing refers to the position of the bracket viz a vie the cage. If the bracket is above the cage, it is a bottom swing. If it is blow the cage (as in your picture), then it is a top swing. The variety is due to frame quirks, such as bottle cage bosses or suspension bits getting in the way of the bracket.

Don't confuse this with top and bottom pull. If the cable enters the FD from the top via the seatpost, it is a top pull. If the cable enters the FD from the bottom, via say, the BB, it is a bottom pull. Nowadays Shimano's FDs are dual-pull but swing-specific.

The FD in your picture is thus top swing and both top pull and bottom pull.

Variations in clamp size are catered for with plastic shims supplied in the box.

 

[Jody]

Not a clue, but why don't you un-seize the current one? It is unlikely to be that badly gone that it is scrap, chuck it in a bucket of old oil for a day or two then give it a forceful talking to. That should do the trick and save you some pennies and heartache.

Tried giving it some WD40 and persuasion but its barely moving. It's £20 for an XT so I smell an upgrade

 

[Jody]

Top and bottom swing refers to the position of the bracket viz a vie the cage. If the bracket is above the cage, it is a bottom swing. If it is blow the cage (as in your picture), then it is a top swing. The variety is due to frame quirks, such as bottle cage bosses or suspension bits getting in the way of the bracket.

Don't confuse this with top and bottom pull. If the cable enters the FD from the top via the seatpost, it is a top pull. If the cable enters the FD from the bottom, via say, the BB, it is a bottom pull. Nowadays Shimano's FDs are dual-pull but swing-specific.

The FD in your picture is thus top swing and both top pull and bottom pull.

Variations in clamp size are catered for with plastic shims supplied in the box.

Great and that's answered my question @Yellow Saddle. The bracket is below the cage and its top pull so M780 should do the trick

 

[Yellow Saddle]

Not a clue, but why don't you un-seize the current one? It is unlikely to be that badly gone that it is scrap, chuck it in a bucket of old oil for a day or two then give it a forceful talking to. That should do the trick and save you some pennies and heartache.

I know it was just an expression but who keeps buckets of old oil handy? There is of course wisdom in your suggestion that a bit of oil and manipulation fixes most frozen FDs and it has to be serious corrosion that ruins one of those. But did you know that just a drop of oil on the joints and a 5-second wait will do the same as dunking it in a bucket? Oil moves into small cavities by way of capillary action and that action is quick - seconds - especially if aided by a bit of joint manipulation. Extra soaking does nothing other than delaying having to fish it from the bucket.

 

[I like Skol]

but its barely moving

If it is moving then it is not seized, you give up too easily. I would hit it with some thicker oil and wash it into the pivots with the wd-40 then keep moving it until it is free. Back off the Hi/Lo screws so it can move further than it needs to and you should have that mech back in service in just a few minutes.....

 

[I like Skol]

I know it was just an expression but who keeps buckets of old oil handy?

Getting OT now but I do

As it happens I was changing the diff and swivel oils in my Defender just yesterday so have them waiting to be poured back into the old container. Mrs Skol is also currently covering around 25k per year on a 10k service schedule so I am doing oil changes on her car every 4-5 months, as well as an annual engine oil change on the Defender (it only does about 3-4kpa). I ALWAYS have a bit of old oil around the place somewhere......

 

[Jody]

If it is moving then it is not seized, you give up too easily.

I know what you are saying but time is at a premium at the minute with a 6 week old baby. I am giving up to easily but for £20 its just not worth the hassle.

 

[I like Skol]

I bet you don't throw away the old one, just in case......

 

[Jody]

I bet you don't throw away the old one, just in case......

I live in Yorkshire. Of course I won't throw it away, we are too tight

Still got plenty of early 90's bits that are fecked and still can't bring myself to bin them

 

[Sixmile]

Wee bit of a thread revival as I fear a public lashing for not searching enough and starting a new thread...

My front mech on my hybrid has seized after a long winter stuck in the big ring. Worst case scenario, if I take it off and can't get it working again is that I need to spend £25 and buy new. My bike is 3x8 and I've seen triple front mechs on CRC, some are 3x9, 3x10 but no 3x8. Surely it doesn't matter as long as it's a triple mech? I can't see how being 8, 9 or 10 matters to the front or does it?

 

[raleighnut]

Wee bit of a thread revival as I fear a public lashing for not searching enough and starting a new thread...

My front mech on my hybrid has seized after a long winter stuck in the big ring. Worst case scenario, if I take it off and can't get it working again is that I need to spend £25 and buy new. My bike is 3x8 and I've seen triple front mechs on CRC, some are 3x9, 3x10 but no 3x8. Surely it doesn't matter as long as it's a triple mech? I can't see how being 8, 9 or 10 matters to the front or does it?

I'd take the chain off and give it a good squirt with penetrating oil then work it by hand, I find leaving the mech on the frame helps hold it still better than trying to hold it in a vice or similar.

 

[Sixmile]

I'd take the chain off and give it a good squirt with penetrating oil then work it by hand, I find leaving the mech on the frame helps hold it still better than trying to hold it in a vice or similar.

I have the chain off and wd'd it. They seemed to work at this stage last year but it's not budging this time. I'll maybe have another bash at it tonight.

 

[mikeymustard]

Wee bit of a thread revival as I fear a public lashing for not searching enough and starting a new thread...

My front mech on my hybrid has seized after a long winter stuck in the big ring. Worst case scenario, if I take it off and can't get it working again is that I need to spend £25 and buy new. My bike is 3x8 and I've seen triple front mechs on CRC, some are 3x9, 3x10 but no 3x8. Surely it doesn't matter as long as it's a triple mech? I can't see how being 8, 9 or 10 matters to the front or does it?

The higher speed fd's are a little narrower so you might need a bit more fiddling to stop chain rub but other than that there's no reason you can't use a 3x9 as a replacement