Author Topic: Help an idiot pick a groupset and understand drive trains  (Read 1924 times)

Corex

Re: Help an idiot pick a groupset and understand drive trains
« Reply #15 on: September 03, 2024, 11:29:44 PM »
It will come as a set that is not in retail packagings, most likely groupsets sold in bulk to bike manufacturers or shops. They get it from Shimano on the cheap and still make a margin by selling at such low prices.

I have been wandering around taobao to see what's in supply and what's not. e.g you still get get such groupsets from aliexpress but it will be a little more expensive compared to buying from taobao and using your own forward shipper.

https://www.aliexpress.com/item/1005005399017410.html?spm=a2g0o.productlist.main.5.23b9M4sBM4sB9M&algo_pvid=9833f71c-8bcb-4c04-8a90-85305c1a20ac&algo_exp_id=9833f71c-8bcb-4c04-8a90-85305c1a20ac-2&pdp_npi=4%40dis%21SGD%211360.88%211320.05%21%21%217189.00%216973.33%21%4021015c7617253793585417534ec266%2112000034587750441%21sea%21SG%21176727628%21X&curPageLogUid=CXTlyBfeGruy&utparam-url=scene%3Asearch%7Cquery_from%3A

the current prices are not as good comparably, but still attractive, I implore OP to go for 105 di2.
Di2 is way out of my budget range sadly haha, and well to clarify this is my first road/gravel bike getting into the hobby so I'm not looking for top performance (whole build is to have something nice to ride around town, to push myself physically on some nearby hill stretches and to have the flexibility to swap out tyres for more rougher terrain exploring the countryside), but I do appreciate not having to mess around tuning gears to wits end just to get reliable shifting.


I have a 2x11 drivetrain on my gravel bike, a winspace g2.

Just my opinion but with a semi internal cable routing gravel build, mechanical-hydraulic hybrid brakes make more sense. Your not going the bombing hills at speeds that make full hydrulic breaking forces useful and usually you will not be able to take advantage of high breaking forces due to lack of traction. Id recommend r7000 shifters and zrace br-005 calipers. Save you about $100 on the groupie

Another thing is the frame will have a certain chainring size limitation for a 2x system. If you are getting a r7000 crankset you can only go as low as 50-34 which likely won't fit. You can use 2-3mm of spacers on the driveside to make it fit but that will impact chainline, but not signifigantly. You would need to go with aftermarket chainrings or just go with a different crankset. I ended getting a senix pr3 w/ 48-32 chainring it even comes in 46-30 if your really worried about it fitting.

Final thing a clutch style derailleur would be nice. I got a rx810 and 11-34 105 cassette. Maxing out the b-limit screw it supposedly can take a 11-40 cassette. I plan on eventually buying a 10 speed goat link and running a 11-42 cassette.
Even if I likely won't fully utilize the benefits of going with hydro brakes my preference lies with them as they're what I'm used to dealing with coming from a heavy MTB background. I was unsure about whether I'll be needing a clutched derailleur but considering that I'll primarily be riding on paved surfaces to begin with I think I'll cross that bridge when I get there. It sounds like rear derailleurs are have limited lower/upper teeth ranges that they work with? So I suppose I'll need to keep that in mind if I do swap it.

I ended up pulling the trigger on that Shimano groupset + drivetrain combo last night so thanks for the heads up that it'll probably have issues fitting the frame that's really good to know. What causes it to not fit? I know you said it's because it doesn't go lower than 34 but what changes fitment wise between say 34 and 32?
« Last Edit: September 03, 2024, 11:42:46 PM by Corex »

Nkearb

Re: Help an idiot pick a groupset and understand drive trains
« Reply #16 on: September 04, 2024, 08:44:24 AM »
Di2 is way out of my budget range sadly haha, and well to clarify this is my first road/gravel bike getting into the hobby so I'm not looking for top performance (whole build is to have something nice to ride around town, to push myself physically on some nearby hill stretches and to have the flexibility to swap out tyres for more rougher terrain exploring the countryside), but I do appreciate not having to mess around tuning gears to wits end just to get reliable shifting.

Even if I likely won't fully utilize the benefits of going with hydro brakes my preference lies with them as they're what I'm used to dealing with coming from a heavy MTB background. I was unsure about whether I'll be needing a clutched derailleur but considering that I'll primarily be riding on paved surfaces to begin with I think I'll cross that bridge when I get there. It sounds like rear derailleurs are have limited lower/upper teeth ranges that they work with? So I suppose I'll need to keep that in mind if I do swap it.

I ended up pulling the trigger on that Shimano groupset + drivetrain combo last night so thanks for the heads up that it'll probably have issues fitting the frame that's really good to know. What causes it to not fit? I know you said it's because it doesn't go lower than 34 but what changes fitment wise between say 34 and 32?

Chainring thing may not be an issue in your case, I havent looked into the specs. The chainstays on a gravel bike are wide to accommodate the large tires. To get a 50c tire to fit, they widen the chainstays so wide that they start interfere with the chainrings and chain. MTB typically have wider bottom bracket area and cranks to account for this. But gravel bikes use road bottom brackets and cranks typically. The specs of the bike should give a max chainring size. If you want you can just add spacers to the driveside of the crank to get more clearance from the chainstays. But you can only add a few spacers until you start having issues fitting the left crank arm.

Corex

Re: Help an idiot pick a groupset and understand drive trains
« Reply #17 on: September 08, 2024, 02:33:03 AM »
Chainring thing may not be an issue in your case, I havent looked into the specs. The chainstays on a gravel bike are wide to accommodate the large tires. To get a 50c tire to fit, they widen the chainstays so wide that they start interfere with the chainrings and chain. MTB typically have wider bottom bracket area and cranks to account for this. But gravel bikes use road bottom brackets and cranks typically. The specs of the bike should give a max chainring size. If you want you can just add spacers to the driveside of the crank to get more clearance from the chainstays. But you can only add a few spacers until you start having issues fitting the left crank arm.

Very insightful, thank you for the information!