Replacing Front Shifter - what else needs replacing?

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netstruggler
Posts: 2
Joined: 18 Nov 2021, 10:56am

Replacing Front Shifter - what else needs replacing?

Post by netstruggler »

My bike is 20 year old Claude Butler hybrid with a Shimano Nexave 3 x 7 groupset.

The chain is 7/8 speed, having been replaced a few years ago.

The problem I have is the (indexed) front shifter has failed (the up paddle has stopped engaging with the ratchet and just flops around). I'm fond of the bike and will spend money to keep it running but I don't want to replace more than I have to.

To that end I've bought a new 3x8 front shifter/brake (Shimano Claris RS203-L 3 speed) combination (7 speed shifters are hard to find)

I've fitted the new shifter and spent a long time on the internet, and outside in the cold setting it up.

I'm 99.9% sure I've got the cable tension as good as it can be and I've checked the stops and derailleur alignment.

The problem is that the new shifter is not throwing the derailleur far enough to reach both the smallest and largest rings.

I can move the barrel adjuster on the lever to get perfect changes between the middle and smallest rings, or between the middle and largest, but not across all three. So it appears the Claris shifter doesn't have enough throw for my Nexave derailleur. As best I can tell, the total throw is about 5mm too short.

The Claris shifter has a 'Lever Stroke Adjustment' which sounded promising but I've screwed it from end to end and it doesn't have any measurable effect on the derailleur throw. (to be honest it doesn't seem to change anything!).

So I either need a derailleur with a bigger throw for the same cable movement or a chainset with a narrower ring spacing (or both).

Any ideas for how I check that before I spend the cash? Most advice I can find online suggests that 3 speed chainsets are generally interchangeable(...but does that include 20-year old 7 speed ones???) and that shifter/derailleur combinations are generally not mixable. So I'm tempted to just buy a Claris derailleur (which is a lot cheaper and easier to fit that a new crank and chainset) and try it; but I rather check before I spend the money. I don't want to buy a derailleur and find it's exactly the same as the one I have.

Another problem is Shimano do both 2403 and 2030 versions of Claris front derailleurs, so I wouldn't be sure which one I needed.

Any advice greatly appreciated.

Regards,

N
rjb
Posts: 7183
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: Replacing Front Shifter - what else needs replacing?

Post by rjb »

I think your issue may be related to incompatible shifting.
See this post.
fastpedaller wrote: 1 Jul 2015, 7:42pm Ok it's fixed - thanks for the help gents. I didn't know Shimano had different cable ratios for MTB or Road for front mech - Very strange, almost as if designed by different departments! :?
Anyway, rather handily, the protrusion at the clamp bolt, which guides and 'supports' the cable proved useful to support the stainless steel extension I fabricated....... A slot to take the cable, and a groove filed on it's front face to clamp the cable against the lever arm (if that makes sense), thus extending the lever length between cable and pivot point by about 7mm.
All seems to work well now - time will tell :|
Here's the whole thread.viewtopic.php?t=98154
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
Pinkie
Posts: 179
Joined: 14 Nov 2021, 1:29am

Re: Replacing Front Shifter - what else needs replacing?

Post by Pinkie »

netstruggler wrote: 18 Nov 2021, 11:11am My bike is 20 year old Claude Butler hybrid with a Shimano Nexave 3 x 7 groupset.

The chain is 7/8 speed, having been replaced a few years ago.

The problem I have is the (indexed) front shifter has failed (the up paddle has stopped engaging with the ratchet and just flops around). I'm fond of the bike and will spend money to keep it running but I don't want to replace more than I have to.

To that end I've bought a new 3x8 front shifter/brake (Shimano Claris RS203-L 3 speed) combination (7 speed shifters are hard to find)

I've fitted the new shifter and spent a long time on the internet, and outside in the cold setting it up.

I'm 99.9% sure I've got the cable tension as good as it can be and I've checked the stops and derailleur alignment.

The problem is that the new shifter is not throwing the derailleur far enough to reach both the smallest and largest rings.

I can move the barrel adjuster on the lever to get perfect changes between the middle and smallest rings, or between the middle and largest, but not across all three. So it appears the Claris shifter doesn't have enough throw for my Nexave derailleur. As best I can tell, the total throw is about 5mm too short.

The Claris shifter has a 'Lever Stroke Adjustment' which sounded promising but I've screwed it from end to end and it doesn't have any measurable effect on the derailleur throw. (to be honest it doesn't seem to change anything!).

So I either need a derailleur with a bigger throw for the same cable movement or a chainset with a narrower ring spacing (or both).

Any ideas for how I check that before I spend the cash? Most advice I can find online suggests that 3 speed chainsets are generally interchangeable(...but does that include 20-year old 7 speed ones???) and that shifter/derailleur combinations are generally not mixable. So I'm tempted to just buy a Claris derailleur (which is a lot cheaper and easier to fit that a new crank and chainset) and try it; but I rather check before I spend the money. I don't want to buy a derailleur and find it's exactly the same as the one I have.

Another problem is Shimano do both 2403 and 2030 versions of Claris front derailleurs, so I wouldn't be sure which one I needed.

Any advice greatly appreciated.

Regards,

N
I dont know if there is an incompatibility issue, maybe, but the fact you've spent a long time doing what is literally a 5 min job makes me doubt your techneque

Take the cable OFF and let the derailer " fall" to its default position, set the limit screw so it stays there and sounds sweet, put both barrel adjusters in the middle of their travel, fit the cable, just pulling the slack out with your fingers

Then change gear, if it doesnt move turn the barrel adjuster till it does, then go up the box, it should now move faultlessly from gear to gear.

If it wont go from gear to gear or reach the end gear, then it's not compatable
Nb some times you need to slackened the adjuster of a midge to get back down again
netstruggler
Posts: 2
Joined: 18 Nov 2021, 10:56am

Re: Replacing Front Shifter - what else needs replacing?

Post by netstruggler »

That certainly looks very on-topic. Thank you rjb

The Shimano Nexave range is described as being for Hybrid / Cross / Trekking / Urban ....

and my new shifter as a: Shift/Brake Lever Flat Bar Road

...and I've even found the helpful comment:
This [Nexave] derailleur is compatible shimano mtn shifters , Sram trigger or grip shifters and shimano bar-con levers , they will not shift properly if you try to use them with Shimano road STI shift levers .
Shame I didn't see that sooner.

So it seems I can either buy an MTB Shifter such as an Shimano Altus and keep my derailleur, or a road derailleur such as the FD-R2030-B and use the new shifter I already bought? I'll think I'll go and count the teeth on my chainset rings again and see if there are any issues there.

Thanks again for the quick (and I'm sure correct) reply.
Eyebrox
Posts: 580
Joined: 5 Aug 2015, 8:56pm
Location: Ayrshire

Re: Replacing Front Shifter - what else needs replacing?

Post by Eyebrox »

Sometimes changing the position of the cable on its approach to the securing bolt can provide extra throw - ie up and over the bolt thread or under and back round. Maybe not as Shimano intended but worth a try.
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531colin
Posts: 16036
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Replacing Front Shifter - what else needs replacing?

Post by 531colin »

As you already found out, Shimano road and MTB front shifting have different cable pulls; you may be able to "adjust" it by altering the cable anchor point on the mech.....you are looking for more mech. movement for the same cable pull.
A cheap way out of your current dilemma is to fit a thumbshifter; as they are not "indexed" they will work either road or MTB front mechs. However, as the original front shifter isn't currently working, there is very little (other than time!) to be lost by trying to get it going. Each paddle has its associated pawl, worked by a tiny pawl spring. When a paddle just flops about aimlessly, all that usually has happened is that the pivot of the pawl had got gummed up with dried-out grease so that the spring isn't powerful enough to move the pawl. There is nothing to be lost by introducing oil into the shifter, and "working" it. (NB....put some tension on the cable, or it can get tangled up in the shifter.)
If that doesn't work, have a good look round the shifter: there are generally 2 tiny cross-head screws which secure a cover, and if you remove the cover you get direct access to the workings, including the gummed-up pawls.
I wouldn't recommend actually dis-assembling the shifter mechanism; many people have dis-assembled them, few have re-assembled them!
TheBomber
Posts: 520
Joined: 16 Feb 2020, 8:18pm

Re: Replacing Front Shifter - what else needs replacing?

Post by TheBomber »

Mrs Bomber’s bike has Nexave gears (3 x 8 ) and the front shifter suffered in the same way as the OP’s. The problem was dried up grease in the shifter. Remove the plastic cover and spray some degreaser in there while repeatedly working the shifter. If you watch carefully you can even work out which bit isn’t engaging.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Replacing Front Shifter - what else needs replacing?

Post by gregoryoftours »

Road flat bar front shifter is incompatible with MTN/hybrid front mech, they are designed to operate different front mechs at a different chainline. Your best option is to buy pretty much any front Shimano MTB triple sti shifter, at least up to 9 speed the left hand shifters are all compatible with your front mech/chainset/chainline (probably 10 speed too but I'm not 100% sure).

Don't buy a Claris or other road front derailleur. These are designed to work on a road chainline, and would therefore require a road chainset. The chainline would then be at odds with your rear gears, and you would also likely have frame clearance issues with the small front ring. The brake levers on the Claris will also be closer to cantilever cable pull than v-brake. I would assume that a 20 year old hybrid bike would be likely to be specced with v-brakes.

Get the part that works with the rest of the bike and how it's designed - ie. get the correct shift lever.
Last edited by gregoryoftours on 2 Dec 2021, 10:56pm, edited 2 times in total.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Replacing Front Shifter - what else needs replacing?

Post by gregoryoftours »

First worth trying flushing the shifter as bomber suggested.
irc
Posts: 5189
Joined: 3 Dec 2008, 2:22pm
Location: glasgow

Re: Replacing Front Shifter - what else needs replacing?

Post by irc »

This would probably work for £10.

https://www.decathlon.co.uk/p/7-speed-d ... R-p-311712

Edit

Probably best ordering online. Decathlon currently have lots of spaces on the shelves due to supply issues.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Replacing Front Shifter - what else needs replacing?

Post by gregoryoftours »

irc wrote: 2 Dec 2021, 10:06pm This would probably work for £10.

https://www.decathlon.co.uk/p/7-speed-d ... R-p-311712

Edit

Probably best ordering online. Decathlon currently have lots of spaces on the shelves due to supply issues.
This is a rear 7 speed shifter. The OP needs a 3 speed mtb front sti shifter/brake lever combo by the sounds of it. Any left hand shifter that is part of an mtb 3x7 to 3x9 set should be compatible.
gregoryoftours
Posts: 2234
Joined: 22 May 2011, 7:14pm

Re: Replacing Front Shifter - what else needs replacing?

Post by gregoryoftours »

Please post a photo of the current shifter, it will make it easier to suggest a compatible component that is also a reasonable ergonomic match. Is the bike fitted with v-brakes? The sti lever needs to match the brake type. (Cantilever or v). If you're on v-brakes and want to replace both front and rear shifters to have a matching pair then Altus mtb 3x7 ez fire shifter/lever sets are still available as well as in 3x8.
Last edited by gregoryoftours on 3 Dec 2021, 6:47pm, edited 1 time in total.
PT1029
Posts: 1742
Joined: 16 Apr 2012, 9:20pm

Re: Replacing Front Shifter - what else needs replacing?

Post by PT1029 »

Trying to ungunge the shifter ratchets is always worth a try. Years since I have looked at Nexave levers, but the upshift lever ratchets can gunge up. Once the cover is removed, thin lube and a thin screw driver/spoke or whatever to jiggle the ratched loose.
I vaguely remember getting the plastic cover off is a lot mor fidly than other models as the cover bits seem to wrap round a lot more. If the small cover screws don't unscrew put some penetrating oil on and leave for a spell to soak in.
The push button (rather than lever) means some of the internals are notably different from other rapid fire lever designs, but one open it is fairly obvious how it all works. You can do this with the cable in situe. Manually putting the chain on the big ring gives you cable slack to play with.
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