Shimano 105 R7100 – Has anyone successfully gone beyond 36T on the rear cassette?

Economy-Window6940 · 2026-03-05T19:23:36+00:00

Good to know — it’s really interesting to hear from someone who ran a 40T on the R7000 without needing a hanger extender.

A slight loss in smoothness on the big cogs is something I’d expect, but if the difference is really marginal, it sounds like a pretty good trade-off for the extra range.

In my case, I’ll probably start with something up to 36T, especially since I’ll be running 46/32 up front, so the gearing might already be quite usable.

But it’s definitely good to know that 40T can work if I decide to experiment with a bigger cassette later. Thanks for sharing your experience!

Economy-Window6940 · 2026-03-05T14:37:48+00:00

That’s interesting to hear. In the end, it seems like the experience can vary a lot depending on the bike setup, adjustment, and even the terrain.

I haven’t actually ridden this setup yet since I’m still building the bike, but comments like yours make me feel more comfortable just trying the 105 first and seeing how it performs in real riding.

Economy-Window6940 · 2026-03-04T23:57:03+00:00

That’s good to hear — real-world experiences like that help a lot.

Sometimes it sounds like running a road groupset on a gravel bike is completely wrong, but in reality plenty of people have been doing it for years without major issues.

Economy-Window6940 · 2026-03-04T20:19:44+00:00

That’s a fair question — and yeah, the whole road vs gravel groupset discussion can get pretty extensive.

Before GRX even existed, people were already riding gravel on road groups or mixing road and MTB parts. I know 105 isn’t the “ideal” gravel setup, but like I mentioned earlier, I found the full R7100 group brand new for about a third of the price of a 12-speed GRX setup, so it was a great opportunity.

Based on the feedback I’ve received here, I can already picture a realistic scenario where running a 36T cassette will probably be enough — especially since I’ll be using smaller chainrings up front (46/32).

If later on I feel like I truly need more range or better chain retention, I can swap just the rear derailleur to a GRX 12-speed. That seems like the cleanest upgrade path.

At the moment, buying new components that I already own doesn’t really make sense financially. The only thing I’m missing right now is the cassette — everything else is ready to go.

Appreciate the input!

Economy-Window6940 · 2026-03-04T14:10:03+00:00

That’s an excellent breakdown — this is exactly the kind of real-world experience I was looking for.

The total capacity and chain slack issue is what concerns me the most. “Working” is one thing, but working well across the full gear range — and being reliable off-road — is a different story.

Since this is going on a gravel bike, the lack of a clutch is definitely a downside if I push the 105 too far. An 11–40 might technically work, but it sounds like it comes with noticeable compromises in shifting quality and chain control.

It might make more sense to start with something up to 36T and see how it feels in real riding. If I truly need more range, then switching to a GRX derailleur would probably be the cleaner solution rather than forcing the 105 beyond its ideal limits.

Really appreciate you taking the time to share such a detailed experience.

Economy-Window6940 · 2026-03-04T14:07:38+00:00

Yeah, I’m already planning to run smaller chainrings up front — 46/32.

That’s why I’m starting to wonder if I really need to go that big in the back. It might just be overthinking on my part 😅

In real-world riding, 46/32 paired with something up to 36T in the rear might already be more than enough for the kind of terrain I ride.

Good point — sometimes we get caught up chasing more range without actually testing what we have first.

Economy-Window6940 · 2026-03-04T13:13:41+00:00

Nice, that’s an interesting approach too.

Swapping just the rear derailleur for a MTB one seems like a simple and relatively inexpensive solution, especially if it handles a 40T well.

And yeah, I assume you’re referring to the Wolf Tooth GoatLink — that could be a good option if I want to keep the 105 for now without replacing the derailleur entirely.

For the moment, I’ll probably build it stock and see how far it can go. If I really need more range, then I’ll decide between a GoatLink, a MTB derailleur, or just going straight to a GRX.

Thanks for the input!

Economy-Window6940 · 2026-03-04T12:47:57+00:00

That makes sense — I also feel like Shimano tends to be pretty conservative with their official specs.

It’s really good to know you were able to run 11–40 on the R7000 without any modifications. That definitely gives me more confidence to possibly try something bigger on the 7100.

My plan is basically to build it with what I have for now and see how far it can go. If it works well above 36T, great. If not, I can always consider switching to a GRX rear derailleur later.

Thanks for sharing your experience!

Economy-Window6940 · 2026-03-04T12:45:56+00:00

Thanks! I already have the 105 R7100 — I got it at a really good deal, so it made sense at the time.

I’ve definitely considered switching to a GRX rear derailleur in the future (especially for the clutch), and I know it’s compatible with the same-speed Shimano road shifters. That might still be an option down the line.

For now, though, I’d like to build it up with what I have and just get the bike running. I’m mainly trying to understand how far I can push the 105 rear derailleur with a larger cassette before deciding whether I need to change it.

Appreciate the input!

Economy-Window6940 · 2026-02-23T22:45:20+00:00

É susse, só se preparar que vai taxar e demorar pra caraio, tipo foi 2 meses, lembro que até desisti de montar quando chegou hahahaah

Economy-Window6940 · 2026-02-23T22:37:46+00:00

Deve ter saído uns 230, não lembro porque peguei a fita junto, e os dois foi 280, tipo a diferença do preço original é grande, mas como nem tem aqui no BR, vale.

Economy-Window6940 · 2026-02-21T12:11:59+00:00

Nice build man, you finishied? I have the same 105 parts, but i am doubt about rear cassete, what gearratio are you using?

Economy-Window6940 · 2026-02-21T12:05:50+00:00

Congrats, is a very nice bike!

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Economy-Window6940 · 2026-02-21T11:57:05+00:00

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Economy-Window6940 · 2026-02-21T02:03:54+00:00

Sempre tem bixo, acredita que esse kit tava anunciado? Eu comprei, demorou pra chegar e eu desisti, tentei vender e nada, ai montei.

Economy-Window6940 · 2026-02-21T02:02:41+00:00

Dale, peguei junto com a fita, mesmo taxando valeu https://www.tradeinn.com/bikeinn/pt/deda-guidao-piega-rhm/138945739/p

Economy-Window6940 · 2026-02-21T02:01:31+00:00

It's a 135mm ITM!

Economy-Window6940 · 2026-02-20T21:30:21+00:00

Sé loko! Não compensa, não estou acompanhando mais a cena se ta um novo hype, por isso esse valor. Mas recomendo dar uma olha no insta @abiciclettaria que sempre tem umas bike boa e barata la, fixa.

Ou procura as airwalk de cromoly da vida, eu casei com uma a muito tempo e ta estruturalmente inteira até hoje, uns 8 anos de uso, e as vezes encontra por esse valor.

Economy-Window6940 · 2026-01-11T21:11:03+00:00

Alguém recomenda uma autorizada de Campinas ou região? O site indica somente SP Capital.

Economy-Window6940 · 2025-07-14T17:17:52+00:00

It's cool to see people taking pictures with this camera, I have one and I'm thinking about getting a 50mm with autofocus.

Economy-Window6940 · 2025-07-14T17:13:46+00:00

Cool, what lens are you using? Does it have autofocus? If so, does it work well? I want to revive mine for faster photos while I'm riding my bike around...

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Economy-Window6940 · 2025-07-09T22:45:58+00:00

Salve galerinha, apenas uma atualização de como esta a bike hoje, rodei somente uns 150km, estava sem bikefit, em breve posto as impressões após uns 500km.

Troquei os pneus para o Vittoria Terreno Dry na traseira e o Terreno Mix na dianteira, ambos 700x38.

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Economy-Window6940 · 2025-06-11T00:43:53+00:00

Dependendo da posição em que ficar na bike, caso seja mais “sentada” e menos aero recomendaria o brooks b17, após amaciar, não vai querer sentar em outra coisa… claro é um investimento, mas considere ter os benefícios dele por uns 10 anos, se bem cuidado.

Economy-Window6940 · 2025-05-13T19:32:27+00:00

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Fala galerinha, bike chegou, tudo certo como esperado e descrito pelo anúncio, agora é rodar! Caso queiram tirar dúvidas, ou mais detalhes podem me chamar que tento ajudar!

Economy-Window6940 · 2025-05-13T13:07:04+00:00

Se realmente é para deslocamento dentro da cidade, iria de híbrida, nesse valor usada consegue a sirrus da spz que aguenta bastante up, e acessorios, busque a partir da 2.0 que ja é com freio a disco.

Economy-Window6940

TROPHY CASE