Cycling UK Forum

Hi nice folk

Thought I'd best double check something.

Please be gentle.

Am thinking of using/packing a pair of downtube shifters as back-ups for three separate kind of touring bikes I have - two 9 speed, one 8.

All flat bar with rapidfires fitted.

I sort of associate downtube shifters with racing bikes, particularly old school.

So thought I had better check if there would be any issue with MTB gearing components as used on my tourers.

Several questions.

If I have things right with 9 speed the indexing on the rear is the same MTB or road?

But different on the front?

So the rear should be no problem indexed?

And the front no problem as I have the impression that most front DT shifters are friction?

Likely to be any additional issue on the front with any difference in front mech configuration? My front mechs are all bottom pull bottom (conventional) swing.#
?

Also if I switch the rear "9 speed" DT shifter to friction fair to assume that I can also use it on the 8 speed bike with an appropriately set limit screw?

Sweep wrote:Am thinking of using/packing a pair of downtube shifters as back-ups for three separate kind of touring bikes I have - two 9 speed, one 8.

Use friction levers. On tour I carry an old friction right hand lever only in case of damage to my ergo levers or derailleur or hangar or anything else that friction will cope with but an indexed lever will not. I do not bother with the left lever because if there is damage on that side it is not such a problem since I could remove the mech and change gear by hand.


Essential stuff - does your frame have brazed fittings to take downtube levers? If not yo uwill have to find and carry a lever clip to suit the diameter of your downtube.

tatanab wrote: I do not bother with the left lever because if there is damage on that side it is not such a problem since I could remove the mech and change gear by hand.


Essential stuff - does your frame have brazed fittings to take downtube levers? If not yo uwill have to find and carry a lever clip to suit the diameter of your downtube.

Thanks for your reply tatanab.

To your first point, hell that's a bit too old school for me - no problems for me to carry a bit of metal left lever.

Second - the two 9 speed bikes have the fittings, the 8 speed is an old ex 7 speed hibrid and doesn't so I plan to get one of these:

http://practicalcycles.com/products/364 ... osses.aspx

from the ever so well named practical cycles.

Other responses to my various questions, particularly from the esteemed brucey, are more than welcome.

yup you should have no problems in shimano systems up to 9s.

RH shifting in shimano MTB 10s requires;

9 x 3.4mm = 30.6mm, and
for MTB 11s you need 10x 3.6mm = 36mm,

which is beyond the capacity of many DT levers.

9s shimano requires a little over 8x 2.5mm = 20mm

Front shifting requires up to ~10mm cable pull per chainring (depending on the mech) so a total cable pull of up to 20mm (similar to 9s rear shifting) but in any event both are within the compass of a 180 degree swing of a DT lever provided the cable wraps around a barrel 13mm in dia or more.

cheers

I must admit that I don't entirely understand your post Brucey - too much expertise your end

But have the impression that all my nervous questions are answered in the affirmative - many thanks.

basically with any DT lever you can only swing it 180 degrees and this limits the cable pull it has. What I'm saying is that some DT levers won't work with some more modern gearing systems (such as MTB 10s or 11s) because they require too much cable pull, but 9s will be OK.

cheers

many thanks for your patience and for clarifying brucey.

Unlikely I will ever move beyond 9.

already storing bits

I substituted a DT shifter for the SRAM Apex brake lever front shifter and it works a lot better, though there's no indexing so I have to trim it a bit sometimes. Luckily it fitted the boss, though it needed a bit of filing as the down tube is not circular section.

A simple trick to increase the diameter of a d/t lever is to slip a short length of electrical sleeving (stripped from a cable when you next rewire a 13 amp plug) over the gear cable after you have inserted it into the lever. Depending on the sleeve thickness this could give you another 1-2 mm on the diameter.

11s d/t friction shifters for MTBs

downtube dynasys 11s
https://velo-orange.com/products/dia-co ... t-shifters

These are bar-con dynasys 11s, probably made by Microshift
https://www.gevenalle.com/product/shift-levers/

For users of British kit, the 11s d/t shifter will pull enough cable to work with CycloBenlux, Mark 7 and Tourist rear mechs.

standard disclaimer, too pricey for ctc use, not available at Aldi.

not sure what your disclaimer is all about, but appear to be US sites.

Which might cause issues for UK folk.