Cycling UK Forum

You live and learn. Those levers passed me by. But then I was an impoverished schoolboy at the time, so Simplex = plastic was as far as my budget went.

The one thing I missed on my hack bike was DT shifters, and recently it broke so I bought a Raleigh eclipse from the eighties with 6speeds and DT shifters. Bottom gear was no good for me in the hills, so I just switched the shifters to friction and grabbed any old wheel hanging in the garage. Now I have 9speeds and a good range. When the cassette needs changing I will use anything I have got in the bits box and it will work. The only thing I had to do was twiddle the max and min screws and and b-pulley screw on the rear mech slightly to accommodate the big ring.

photo below shows a LH simplex lever disassembled, together with some of the matching parts from a RH lever.



you can see how the drag springs are wound so that pulling the lever back 'unwinds them' a little, so that they lose their grip on the drum part, and by contrast pushing the lever causes the drag spring to wind tighter on the drum. The drum friction is controlled in the normal way, by screw-preloaded friction washers. Obviously when the lever is working normally, the drum only ever turns in one direction (when paying cable out of the lever) and this helps the friction adjustment stay put.

The drag springs have an ID (when free) ~0.3mm smaller than the OD of the drum; this determines the preload on the action, and thus both the force when pulling the lever back as well as the chances of the drag spring slipping when pushing the lever away. Very well used levers can run out of preload; wear occurs on both the drum and the spring.

The lever, drum and drag spring come out of the assembly in one piece; to separate them it is sufficient to just push the drum firmly. However if you can hold the drum so that it cannot rotate, you can pull the lever round (so that the drag spring slips on the drum) and disassembly is a made a lot easier.

Both these levers (they are from different sets) felt OK but were actually full of dried grease and the grease hadn't inhibited corrosion properly. The LH drag spring has been cleaned slightly and the RH one has not.

The dummy bosses (which fit over standard braze on bosses) use (in typical simplex style) the square base as a location; the flats near the end of the lever braze-ons don't play any role in proceedings. This makes these levers a good choice if you have slightly dodgy braze-on bosses with worn flats on them. It also means that the braze-on pattern levers (as depicted) fit a wide range of band types; for example a Huret band can be used with these levers.

BTW the (adjustable) clutch in shimano dynasys 'clutch' mechs works in a similar way, i.e. is runs slacker and moves freely in one direction, but self-tightens and creates a lot of friction in the other.

cheers

cheers

Has anyone here tried the SunRace 9sp index only downtube levers?

reohn2 wrote:Has anyone here tried the SunRace 9sp index only downtube levers?

Ello!

I use them on my take offs. I'm still trying to decide if I like them or not as I've nothing else similar to compare with.
I can get most of my gears indexed nicely but there's always a couple that will under or over shift. The left lever is friction but has lots of little clicks from one ring to the next. I've gotten used to it now and can roughly guess how much to move the lever to change gear quickly.
I'm not keen on the sharp edges or the flat as a ruler shape of them but otherwise they seem to work.

Thanks Bill,I've ordered a pair to replace the bar end levers fitted in my Kelly's.TBH I'm baulking at £70 for 9sp Dura Ace D/T levers.

Brifters are very dear and I’ve heard an early pair of 105s pack up after about 12 years and they’re a big part of what ties you in to a set number of speeds. Recent builds of mine have been with the Dura Ace indexed d/t levers, the Dia Compe friction shifters and Shimano 600 band on shifters, all with 10 speed systems. All work well for me.

re the sun race shifters; I've not used the DT ones but I have used plenty of Sun Race thumbshifters. I think the indexing is built the same way in both, and if so it is a ball/indent style indexing (as in fact most DT levers, thumbshifters and even Sun Tour 'command' shifters work this same way) then it is likely to be in the 'good but not quite perfect' category.

The devil is in the details; it is important that the indexing mechanism doesn't have any backlash vs the lever, or if there is backlash, the lever itself moves freely without sticking, and that any backlash doesn't get worse through wear. Also the detent plate should be made of very hard steel so that it doesn't wear, and the preload on the mechanism is kept constant by using well-designed springs acting through parts that don't wear away and alter the preload.

The Sun Race indexed thumbshifters I have dealt with just aren't quite as well made as some others are in these respects and it shows; they are not quite as good when new and they wear a fair bit more quickly too. I think they will wear about x10 faster if you let water get inside them and when they are not properly lubricated; all the really knackered ones I have seen have clearly had water inside them. The rubber boots quite often pull off the thumbshifter lever too. Probably they are still good VFM, given that they are about half the price of shimano ones.

The LH thumbshifter is a 'powershift' type that pulls about 1.9mm per click; it is a pretty good match for a MTB FD, but the clicks are a bit coarse for a road FD. I don't know about the DT version, but I'd imagine that it is similar but a shorter pull per click. IIRC the thumbshifter version has 36 clicks and they are not quite evenly spaced; one cable pull is a fraction of a mm different to the other 35. In tests, ( I often use a sun race LH shifter for working out RD shift ratios) the ratchet doesn't work properly and skips a tooth before it settles on a downshift; I think that this may eventually cause enough wear/damage to be a problem.

I have a feeling that the thumbshifter workings will mount onto some DT type bosses (perhaps with a little adjustment/modification), since the mounting also uses a square location at the base. However I have not yet tried it to be sure, and this will mean losing the cable stop for sure. Likewise the clamp is 22.2mm but
a) this could be machined out and/or
b) Sun race also make larger clamps in the same pattern eg for the S3X shifter that mounts on a seatpost.

this means that there is potential to mount these levers in different ways that might be useful for some folk.

cheers

Since we’re sharing the down tube shifter love, here’s a pic of the friction shifters on my racy bike from BITD:


Although I’ve replaced the brake inner cables I’m pretty sure I’ve kept the original gear cables. Not long after I bought that bike Shimano came out with this new-fangled “indexed gears” business. I think I’m starting to get over the feeling of missing out. Some more nostalgia for those in the mood...

http://cycleseven.org/raleigh-roadace-shimano-600

My mid 80's touring bike has the same Shimano 600 dt levers

I've got DA ones on my 80s race bike. And I should have some 600s knocking around somewhere from another bike that has been upgraded to 8-speed Ergos.

reohn2 wrote:Has anyone here tried the SunRace 9sp index only downtube levers?

I got my SunRace 9sp DT levers today and fitted them in the Kelly's on my Genesis Vagabond.
Quality is not Dura Ace standard but very good nevertheless,indexing is very positive on the RH lever with slick shifts,but sadly no friction option.LH lever is friction only with a ratchet like the old SunTour DT levers I had BITD.
Overall,upto press I'm impressed,and particularly like the Allen retaining bolt instead of Shimano's slotted bolt which has always puzzled why Mr S persists with it
One other thing,if you're thinking of a pair to fit onto Kelly's they come with a profiled bezel to fit neatly around a 28.6mm DT which will need filing flat to fit Kelly's properly.

reohn2 wrote:particularly like the Allen retaining bolt instead of Shimano's slotted bolt which has always puzzled why Mr S persists with it

Me too. Anyone know why? Though Shimano must have done something right in the design because those screws have never loosened in my use.

reohn2 wrote:I got my SunRace 9sp DT levers today and fitted them in the Kelly's on my Genesis Vagabond..

link please for where you got them from?

Sweep wrote:

reohn2 wrote:I got my SunRace 9sp DT levers today and fitted them in the Kelly's on my Genesis Vagabond..

link please for where you got them from?

Sorry meant post that,these people :- https://www.ebay.co.uk/itm/Sunrace-7-8- ... 2749.l2649