Author Topic: Advice please  (Read 2065 times)

Re: Advice please
« Reply #25 on: June 23, 2018, 09:04:03 am »
Beware that some Schlumpf systems (HSD) can exceed the torque recommendations and invalidate the Rohloff guarantee
Only the Schlumpf MD can exceed the torque limit because it a step down system which give you more low gears. To stay within the limit you need to run sprocket x 1.9 x 2.5 = minimum chainring which gives you something like a 62:13 chainring:sprocket combo.

Both the SD and the HSD are step up systems which give you more high gears. So as long as you initial chainring:sprocket ratio is better than 1.9:1 then your fine as the bigger virtual chainring gives you less torque at the hub.

I have a 20" rear wheel which limited the choice of ratios on the HSD

Essentially the systems have the same issues

Re: Advice please
« Reply #26 on: June 23, 2018, 12:07:28 pm »
I have a 20" rear wheel which limited the choice of ratios on the HSD

Essentially the systems have the same issues
I had no problem with the gear range with my Rohloff-Schlumpf combo.
But it did take me a bit of lateral thinking to get what I consider the best chainring-sprocket combo.
I started with the 30 sprocket and used either the 13 or the 16 sprocket depending on the gear range wanted.
The 13 sprocket was used around town as the overdrive shift was around 20 mph.
The 16 sprocket was used on tour to give me a sub 10" first gear.
This worked great but changing sprockets was a PITA.
So I thought with a single sprocket and twin chainrings I can get the same combo ranges in one setup.
The minimum sized chainring on the spider is 38t which gives you a recommended 19t sprocket, but I went for the  non-recommended 21t sprocket for a sub 10" first gear.
Then for the big chainring I tried to get an exact number of gears steps above the small chainring.
A 3 gear step is 38 x 1.136^3 or a 56t chainring.
But the 56t chainring is to big for the chainguard so I've ended up with a 55t chainring.

The only downside, apart from the odd triple shift, is the spider is only held in place by a circlip, so get the shift wrong and you can pop it.
But you soon learn to treat the shift similar to a hub gear one and don't shift under load.

Re: Advice please
« Reply #27 on: June 24, 2018, 11:05:56 pm »
For me it was an open air swimming pool shallow end with an inflatable kids Indian canoe getting swarmed and bitten. Plus a tide line of drowned ladybirds.

Re: Advice please
« Reply #28 on: June 27, 2018, 08:04:40 am »
Thanks all for the advice. After a lot of research and prevarication I’ve splashed the cash on some changes.

I’m replacing the 170mm SRAM cranks with TA Carmina 155mm cranks, with 110 BCD 5 arm spiders which enables me to put on double absoluteBlack oval chainrings with 36 and 50 teeth to marry up to an 18 tooth Rohloff cog at the rear. That will give me something like 13” - 100” gear range which should suffice for my touring purposes. I chose to skip on the Schlumpf drive as I’m told you can’t fit the recommended oval chainrings to it, personal choice in the end. Chris at ICE tells me they DO offer LASCO 152mm cranks, but only with 104 BCD spiders that limits the choice of chainrings, where the TA ones enable you to use spiders with 104, 110or 130 BCDs.

I’ve also ordered a Marathon Almotion rear which the write ups say is faster rolling, has more grip and more puncture resistant than the Big Apples I’m currently running. That should reduce the rear wheel spin on wet tarmac, especially when coupled with lower gears and oval chainrings.

I’ve bought the ICE rain cover for the seat.

In the hot weather I’ve appreciated the draught up the legs of the shorts more than I’ve feared the bee-attack! However, I will look to get some MB shorts with Velcro for when it cools down a bit.

On an aside, it turns out my Rohloff was faulty and ICE are swapping the wheel over this week, I’m guessing not many Rohloffs have faults given their QC?

Once again, thanks for all the advice. I may post again to report on what if any difference all this extra plunge has made on the issues I was experiencing.

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