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-   -   Racer Tech Thread (https://www.bikeforums.net/33-road-bike-racing/956936-racer-tech-thread.html)

UmneyDurak 11-25-16 06:25 PM


Originally Posted by spdntrxi (Post 19213482)
I have not done much research on 9150.. but I heard it has synchro shift... I'm happy with current DA and 6870.. so I'm good.

Synchro shifting?

spdntrxi 11-25-16 06:33 PM

This technology allows you to shift to higher or lower gears with your right hand shifter and both front and rear derailleurs will operate to optimise chainline. It will also automatically shift the rear mech when you change from the large ring to the inner ring to maintain smoothness.

googled

shovelhd 11-25-16 09:48 PM

That's a long winded way of saying that it shifts the FD and/or RD to progressively step through the gears in ascending or descending order.

tetonrider 11-25-16 11:30 PM


Originally Posted by UmneyDurak (Post 19212429)
PBK is having sale onShimano Ultegra Di2 6870.
I am seriously considering getting it. Anyone regret going to electronic shifting, and anything I am missing? Like a better version around the corner, etc?

Thanks

there is a newer version that is about to be released, but it is pretty marginal in terms of improvements.

arguably the biggest feature ("synchro-shift," which has been a staple of their MTB di2 group for a few years, for those few MTBers left who use a front derailleur... ;-)) is actually going to come to 6870/9070 via a firmware update.


Originally Posted by echappist (Post 19212650)
there's a new A-junction (EW-90) that supposedly fit into the end of a handlebar. Much better form factor than what they currently have

keep in mind one will need bars that allow wires to enter at the shifters and exit near the stem/bar interface.


Originally Posted by Doge (Post 19212748)
I thought that was a big deal, then I wired my A box under the seat on the 9000. don't know why I didn't do this before.

the only trouble is that some people need/want on-the-fly adjustability (and want to see if it is in adjust mode). the under-the-saddle mount eliminates this -- or at least makes it tougher.


Originally Posted by spdntrxi (Post 19213482)
I have not done much research on 9150.. but I heard it has synchro shift... I'm happy with current DA and 6870.. so I'm good.

coming to 6870 & 9070 via firmware update. not clear if the new battery will be required, though.

Doge 11-25-16 11:56 PM


Originally Posted by tetonrider (Post 19213840)
the only trouble is that some people need/want on-the-fly adjustability (and want to see if it is in adjust mode). the under-the-saddle mount eliminates this -- or at least makes it tougher.
...

Yea, well, for this forum, speed is what [should] matters most. You know we have 4 of these setups at our house. This is the cleanest and fastest.

Stage races might be different as you need to adjust to a random spare - maybe. Otherwise, tune it before you race it.

Doge 11-25-16 11:58 PM


Originally Posted by spdntrxi (Post 19213496)
This technology allows you to shift to higher or lower gears with your right hand shifter and both front and rear derailleurs will operate to optimise chainline. It will also automatically shift the rear mech when you change from the large ring to the inner ring to maintain smoothness.

googled

I don't believe it. There is still this belief that a 44X11 is as good as a 56X14. It just ain't so.

tetonrider 11-26-16 12:41 AM


Originally Posted by Doge (Post 19213853)
Yea, well, for this forum, speed is what [should] matters most. You know we have 4 of these setups at our house. This is the cleanest and fastest.

Stage races might be different as you need to adjust to a random spare - maybe. Otherwise, tune it before you race it.

if we were in a TT forum, i'd agree 100%!

but this is more general road racing. getting a neutral wheel that may not shift properly & need to be adjusted on the fly is a possibility in racing.

improper shifting could be slower than a stem-mounted A-junction.

spectastic 11-26-16 01:24 AM

just as i'm about to take off my stupid bb30 bearings to put in the adapter that could convert the frame into BSA, I find out that my frame's bb shell is butted... so now, I'm going to have to to with wheels mfg outboard..

only thing i don't like about cannondale, is the stupid pressfit trend that they started.

topflightpro 11-26-16 02:34 AM


Originally Posted by spectastic (Post 19213904)
only thing i don't like about cannondale, is the stupid pressfit trend that they started.

IIRC, Klein did it first.

As for electronic, I'm waiting for eTap. Currently, it's not available for employee purchase. I'm waiting for that availability.

spectastic 11-26-16 07:50 AM


Originally Posted by topflightpro (Post 19213918)
IIRC, Klein did it first.

As for electronic, I'm waiting for eTap. Currently, it's not available for employee purchase. I'm waiting for that availability.

what's the employee price?

Doge 11-26-16 11:48 AM


Originally Posted by tetonrider (Post 19213840)
the only trouble is that some people need/want on-the-fly adjustability (and want to see if it is in adjust mode). the under-the-saddle mount eliminates this -- or at least makes it tougher.

Can't help the see part, but in practice it is just push the button 3 sec and then adjust while riding. You know you are in that mode because of the RD movement so seeing the red light or not would not matter. Also the battery indicator would not be showing, so you'd have to be one of those that does not need to see a low battery indicator light to know you have a low battery.

Doge 11-26-16 11:50 AM


Originally Posted by spectastic (Post 19213904)
just as i'm about to take off my stupid bb30 bearings to put in the adapter that could convert the frame into BSA, I find out that my frame's bb shell is butted... so now, I'm going to have to to with wheels mfg outboard..

only thing i don't like about cannondale, is the stupid pressfit trend that they started.

If outboard means wider bearing spacing - that is a good thing, all else still working.

Doge 11-26-16 11:53 AM


Originally Posted by tetonrider (Post 19213881)
if we were in a TT forum, i'd agree 100%!

but this is more general road racing. getting a neutral wheel that may not shift properly & need to be adjusted on the fly is a possibility in racing.

improper shifting could be slower than a stem-mounted A-junction.

I was vague on stage racing in my post you commented on...
In general on single day races junior does, if there is a flat, the race is over. Your point about adjustment, I agreed with which is why I mentioned stage races.
But he's been using and adjusting with no issues while riding, so I'm not sure the SR thing/spare wheel even matters.

ancker 11-26-16 01:15 PM


Originally Posted by spectastic (Post 19214061)
what's the employee price?


Before I gave up and bought online, I had it ordered through a local shop.
I watched them while they set up the order in QBP, the shop price was around $1100. List price is $1660. (for upgrade group)
Not sure if you can infer employee pricing from that, but there ya go.

globecanvas 11-26-16 03:43 PM


Originally Posted by tetonrider (Post 19213840)
the only trouble is that some people need/want on-the-fly adjustability (and want to see if it is in adjust mode)

You really don't need to see it to use the adjust mode.

tetonrider 11-26-16 05:28 PM


Originally Posted by globecanvas (Post 19214808)
You really don't need to see it to use the adjust mode.

which is why i wrote this:

some people need/want on-the-fly adjustability (and want to see if it is in adjust mode)
:)

improved aerodynamics seems likely (and very small) but untested. reduced usability has to be weighed against this.

my point is that any reduction in usability may offset the (very) small gains in aerodynamics. it doesn't take many seconds of having to sit upright and hold down buttons for a few seconds longer to make sure its in/out of adjust mode when you can't see it to offset those gains.

now, if it's an all-out TT...

spectastic 11-26-16 07:16 PM


Originally Posted by Doge (Post 19214466)
If outboard means wider bearing spacing - that is a good thing, all else still working.

all marketing jargon if you ask me. I care more about cross compatibility between my bikes.

furiousferret 11-26-16 07:54 PM


Originally Posted by spectastic (Post 19213904)
just as i'm about to take off my stupid bb30 bearings to put in the adapter that could convert the frame into BSA, I find out that my frame's bb shell is butted... so now, I'm going to have to to with wheels mfg outboard..

only thing i don't like about cannondale, is the stupid pressfit trend that they started.

I had the exact issue with my CAADX. Praxis didn't work so we had to use Wheels Mfg.

spectastic 11-26-16 08:11 PM


Originally Posted by furiousferret (Post 19215264)
I had the exact issue with my CAADX. Praxis didn't work so we had to use Wheels Mfg.

why didn't praxis work? because it's too fat in the middle

but I'm glad to know that mfg works, bucause i already placed the order..

Doge 11-26-16 09:20 PM

While marketers tend to market what they can, that is a separate issue from what works better.
Wider bearings (all else being the same) always work better. It is just the ratios of lever arms - not marketing.

spectastic 11-26-16 10:16 PM


Originally Posted by Doge (Post 19215420)
While marketers tend to market what they can, that is a separate issue from what works better.
Wider bearings (all else being the same) always work better. It is just the ratios of lever arms - not marketing.

better how?

Doge 11-26-16 10:50 PM


Originally Posted by spectastic (Post 19215490)
better how?

Just like a 52X13 is less stress, less energy loss than a 44X11.

The bearing width is 58 c-c OR outbound 78 c-c.

Not dealing with units - just ratios, a stance width (http://www.slowtwitch.com/Tech/Stance_Width_2562.html) of 150stance width / 58 bearing c-c = 2.6 vs 150stance width / 78bearing c-c = 1.9. Or over 30% difference in torque the BB and bearings need to deal with.
This is assuming everyone pushed straight down on pedals and ignoring all the hard twisting math dealing with crank arm lengths.

To see how much that matters you would have to know the force vector on the pedals and crank length, but the ratios are going to be the same. Tooling along I doubt it would be noticed. In a sprint, it is just one more thing to eliminate/reduce. So yea - I always spend the money to add outboard bearings (and bigger rings) - any brand - it is just better.

furiousferret 11-27-16 12:43 AM


Originally Posted by spectastic (Post 19215299)
why didn't praxis work? because it's too fat in the middle

but I'm glad to know that mfg works, bucause i already placed the order..

It was a tad too wide on the edges.

shovelhd 11-27-16 07:27 AM


Originally Posted by Doge (Post 19215518)
Just like a 52X13 is less stress, less energy loss than a 44X11.

The bearing width is 58 c-c OR outbound 78 c-c.

Not dealing with units - just ratios, a stance width (Stance Width - Slowtwitch.com) of 150stance width / 58 bearing c-c = 2.6 vs 150stance width / 78bearing c-c = 1.9. Or over 30% difference in torque the BB and bearings need to deal with.
This is assuming everyone pushed straight down on pedals and ignoring all the hard twisting math dealing with crank arm lengths.

To see how much that matters you would have to know the force vector on the pedals and crank length, but the ratios are going to be the same. Tooling along I doubt it would be noticed. In a sprint, it is just one more thing to eliminate/reduce. So yea - I always spend the money to add outboard bearings (and bigger rings) - any brand - it is just better.

But you can't ignore the hard twisting math. Minimizing that twisting is the whole point of BB's like BB30. Make the bearing and bearing shell (frame area) as large as practicable. Make the spindle as short and as large in diameter as possible within that boundary. This minimizes twisting torque on the frame, which optimizes torque to move the bike forward.

Doge 11-27-16 11:07 AM


Originally Posted by shovelhd (Post 19215777)
But you can't ignore the hard twisting math. Minimizing that twisting is the whole point of BB's like BB30. Make the bearing and bearing shell (frame area) as large as practicable. Make the spindle as short and as large in diameter as possible within that boundary. This minimizes twisting torque on the frame, which optimizes torque to move the bike forward.

I was commenting on part of the system. Specifically bearing pressure. And while I don't know all the forces (esp when the chain is involved) I do know that wider spacing will have less bearing pressure than narrow - ~30% less. The bottom bracket issues are the same, as are the cranks and pedals - and the spindle. I just don't see how any of that changes that the wider bearing stance means less pressure on the bearings - all else being equal.
We have several BB30 and Shimano setups. Junior started riding his S-Works with the S-Works BB30 cranks then switched to the DA - with outboard bearings. He said he noticed. Doesn't matter so much if he did, or didn't it is just one little space that is now a bit stiffer.

Everything is better now, but in the day of thin BB spindles on flexy frames - esp tandems, you could see and feel stuff twisting. I had experience with square taper Phil Wood BB (close bearings) vs a Campy, vs the later outbound Magic Motorcycle (bought by Cannondale) on my four tandems. That is where bearing placement became a big deal to me. There it could be felt and seen. Now - maybe hard to see or feel, but the principles are the same.


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