Wondering about the fastest, while wide-range, drivetrain

DavidCH

In thought; expanding the paradigm of traversity
I am going to replace the brake cables pretty soon , I also want to swap out the brake levers as it was only a proof of concept. Sram do some pretty good aero tt brake levers that could be a good buy. The disk brake pads ought to be swapped out for something better too. The heat this year is crazy hot. The tubeless front tyre has probably dried out after just 4 months so that probably needs looking at too.
 

Frito Bandito

Zen MBB Master
I am surprised the GP 5000 dried out so quickly David. I thought the Michelin Power Competition I have on my commuter dried out quickly, but dang. I won't be buying the Michelin's again though because of that.

As for the brake levers, I haven't tried SRAM's TT brake levers, but my Campagnolos look similar to the ones you now have on your V20. I can pull on mine when putting out more power but they really aren't that comfortable then.
 

Alanczik

Member
Hi @Tor Hovland , here are the photos.

I am thinking about getting the medium sized chainstay as i have a large , which is too horizontal for me with hills. I think the optimum is something in between.

The cranks are 155mm.

I'm a bit adventurous with the brake cables but I check for fraying every time I go for a ride. But there is like very little drag.

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No no no no!!!!!!
Im sorry sir but your front and rear brake cable roting is very wrong, please change as soon as possible!
 

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DavidCH

In thought; expanding the paradigm of traversity
Yep... I can understand your concern. I check this , every ride.
 

ratz

Wielder of the Rubber Mallet
No no no no!!!!!!
Im sorry sir but your front and rear brake cable roting is very wrong, please change as soon as possible!
LOL if you ever meet David in person; it will make so much more sense.

We love you David you do you. :)
 

DavidCH

In thought; expanding the paradigm of traversity
¿Front-wheel drive derailleur?
I think the front wheel drive derailleur is fine. I think there was a weak piece of plastic in the forward brifter's gear ratchet that broke but I think it's been upgraded now.
 

Tor Hovland

Well-Known Member
I can't believe it's almost 3,5 years since I started this thread! What can I say? I like to take my time pondering my options :)

Anyway the WickWerks chainrings suggested by @3bs sounded like a no-brainer for anyone looking for more range. This is how my setup looks now:

PXL_20230918_151855702.jpg

So how big cassette can I run with this? OK, so my wonderful Shimano Deore XT RD-M8000 has 47T capacity. I want to be able to use all the cogs when I'm on the big chainring. Obviously I want to be able to use the small cogs, but I also want the chain to be long enough for big-big, because I don't want to ruin my drive train with one badly judged gear shift. On the small chainring I obviously want to be able to use the big cogs. The small ones are less important. And particularly the small-small combination is of no use.

So, if I mount an 11-40T cassette, 47T capacity is enough to be able to use the entire cassette on the small chainring, except small-small. Perfect! But can I go to 11-42T? Sure, I just lose one additional small cog. That's really no problem. How about 11-46T? Well, now I lose the 4 smallest cogs, plus the big cog is too large for the derailleur. So 11-42T is what I have on. And the theory and practice actually match up in this case, because the chain does skip when using the two smallest cogs with the small chainring.

Screenshot_20231004_212107.png

So there you have it. Although I do wish I could have even wider gearing, on both ends, I feel like this is as good as it gets for now. And to be honest, it is good enough. The one thing that would take this to the next level would be a 10T cog, but only SRAM has a 10-42T cassette, and for that I would have to change to an XD hub.
 

Tor Hovland

Well-Known Member
I haven't done the mod above yet. I'm running the WickWerks 53-34 with the 11-42 cassette, using my M8000 XT derailleur and the Jtek Shiftmate.

Unfortunately, I cannot get it to shift perfectly. It sort of works, but I cannot have the wire slack enough to easily drop down to the 11T while tight enough to easily shift up to the 12T. And I cannot bring the chain closer to the cassette with the B-screw without getting into trouble with the 42T cog.

I'm not sure if the Jtek is contributing to this problem. I suspect I will get similar results if I do the GRX/XT hack I mentioned above.

But I think I will do the hack anyway, just to get the Jtek out of the equation, and if shifting isn't perfect then, I will reduce capacity until it is.

However, maybe there are other, even longer, cages I can use instead of the M8000.
 

Tor Hovland

Well-Known Member
Actually, I didn't wait, I reduced capacity already. I didn't have any 11-40 cassette to try, so I mounted an 11-36. I adjusted the B-screw and shortened the length by two full links (four half links). It seems to be shifting properly now, but I need to get out and try it on the road.

Unfortunately, this is a range of only 510%. Before the WickWerks chainrings, I had 561%, but that was with only a 50/11 top gear (and 34/42 low). If I where to use a standard 53-39 crank with the 11-42 cassette, I would get 519%. So just a tiny bit more.
 

Andreas

Active Member
Thanks for posting this Mod. GRX 812 and the XT spares are now laying around here and waiting for a rainy day. The cassette is still to be ordered, either Deore, SLX or XT, I think I'll get the one in the middle.
But do you really need an 53T ring on rides where you have to use 34/42?
I think about having separate sets of chainrings for local rides and Brevets.
If we are lucky, both chainrings on a 105 crank may be changed without removing the crank (but not sure).
 

Tor Hovland

Well-Known Member
Thanks for posting this Mod. GRX 812 and the XT spares are now laying around here and waiting for a rainy day.
I also ordered them today.
The cassette is still to be ordered, either Deore, SLX or XT, I think I'll get the one in the middle.
Keep in mind that while a 47T capacity will allow you to run run an 11-42 cassette whether you run 53-39 or 50-34 up front, I think you will get better shifting if you go down one size to 11-40. That should be a better option unless you absolutely need the 42T.
But do you really need an 53T ring on rides where you have to use 34/42?
Yes and no. Any hilly ride around here will also have stretches with a slight descent, or a flat tailwind. But you are right in that I probably don't care about going super fast in that case.

But do I really want to change chainrings or cassette, and adjust my derailleur, and change my chain, before each ride?
If we are lucky, both chainrings on a 105 crank may be changed without removing the crank (but not sure).
Honestly, if you want to go that route, I think it will be easier to change the entire crank.
 
I'm not sure this is relevant to the thread, but I'm running a stock Shimano R8000 drive train with an 11-40 cassette and I'm very happy with its performance. There is a slight degradation in shifting performance vs a smaller cassette but it's worth it to me. Here are components:

FC-R8000 (50-34) 165mm
CS-M8000 (11-40) -- Only non R8000 part
FD-R8000
RD-R8000 GS cage
ST-R8000

I can shift into big-big and small-small with only the normal cross-chaining issues. I do take the time to carefully tune the cable tension and limit screws and don't let the chain wear down too much. The B tension is adjusted based on shifting performance while in the stand.

Greg
 

Tor Hovland

Well-Known Member
Sure, that's relevant!

I actually have that derailleur myself. I've used it when I haven't needed such a big cassette. It's amazing if you can get it to work well with an 11-40. That's a 45T capacity, and the derailleur officially only supports 39T, with 11-34 as the widest cassette. But we know these numbers are somewhat conservative, and can be exceeded.

By the way, take what I wrote above about the 11-42 with a grain of salt. I've found that even with an 11-36 I am not having perfect shifting. I suspect the Jtek is not giving a 100% accurate translation. I'm hoping that the hacked GRX will solve this, even with an 11-42. Time will tell.
 

Tor Hovland

Well-Known Member
I got a package in the mail yesterday which will let me update not one, but two threads on this forum :)

PXL_20240404_143948972.jpg

This thread is about the derailleur and the long cage spare parts.

When mounting the new, unhacked derailleur, I noticed that it wasn't hanging straight below the cassette. That's odd. I took a closer look at the derailleur hanger, and it does indeed look a little warped:

PXL_20240404_160814877.jpg

I looked around for another hanger, but I guess I forgot to get one when I picked up this second-hand V20 frame. If anybody has any extra to sell, let me know!

Anyway, I just bent it back so the derailleur looks straight now.

As a new baseline, I am happy to say that it looks like I now have reasonably precise shifting. I just need to go for an actual ride to confirm. There are several reasons why things might have improved:

- The straightened hanger.
- A brand new derailleur. The old one feels like it needs a full service.
- No Jtek shifting adapter.
- I'm still running the slightly less monstrous 11-36 cassette.

I'm not convinced things will work nicely with the 11-42 cassette. But whether or not I want to run that big cassette, I will still try to hack the derailleur. In its current form, there are several gears that are now unusable on the small chainring. The longer cage should fix that.

I'm going to leave things as they are for now, as I have a 200 km ride on Sunday. I'll be experimenting with the longer cage following that.
 

Andreas

Active Member
I've already converted the GRX to the long cage and replaced the 105 RD.
The 11-32 cassette is still on. I'll probably only use the 42 for Brevets and longer rides the Alps, but for local speed rides, I love and need the 1-tooth jumps of my Sram PG-1130 (11-12-13-14-15).

I've already completed 3 rides with it, and the small cogs shift just as well as with the 105 RD, and big/big works better now.
I haven't adjusted the chain length yet (118 links). I'll probably need to add 6 links for the 11-42.
But even the longer chain should work fine with the 11-32 cassette.
In small/small, the cage is still angled downward at the current chain length and would then just move further back.

So it looks like I won't need to change the derailleur or chain when changing the cassette.
Amazing, thanks again for that Mod, @Tor Hovland.
 

Tor Hovland

Well-Known Member
Sure, no problem.

I had a test ride today, and unfortunately, I still don't have perfect shifting. This is with the unmodded GRX and the 11-36 cassette. If we forget about the small chainring for a moment, the derailleur supports an 11-42 cassette, so shifting should indeed be perfect as long as I stay on the large chainring. I suppose this means my hanger needs to be straightened properly. I am going to buy a tool for that.

The saga continues. But I will get to the bottom of this.
 

Andreas

Active Member
Sure, no problem.

I had a test ride today, and unfortunately, I still don't have perfect shifting. This is with the unmodded GRX and the 11-36 cassette. If we forget about the small chainring for a moment, the derailleur supports an 11-42 cassette, so shifting should indeed be perfect as long as I stay on the large chainring. I suppose this means my hanger needs to be straightened properly. I am going to buy a tool for that.

The saga continues. But I will get to the bottom of this.
In which position is your lever switch?
I was initially a bit confused about this switch and then went searching.
The manual says that the 'Off' position is for wheel removal, but other sources say 'On' for bumpy trails, 'Off' for roads and better shifting.
Therefore, mine is set to 'Off'.

Regarding your hanger:
Mine was also bent. But I was lucky to have a spare hanger as a reference and was able to fix it without additional tools using the 'second wheel' method: Link
 
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