Login required to started new threads

Login required to post replies

Prev Next
Anybody riding a disc and 80 front all the time
Quote | Reply
I’m finally getting a new tt bike yay me!

I already have a road bike so am planning to get a race ready tt bike with disc and 80mm front. I’m assuming I will need valve extender for the front and different tube stem sizes to accommodate both the front and disc as the disc likely needs a super short stem tube.

Any problems or things to worry about this sort of setup for training? Other than having to carry 2 different types of tubes?
Last edited by: lightheir: Apr 1, 21 6:19
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
You could get away with just one tube: stem length to match the disk, and if the 80 goes, just use the extender from the flat. you might need a slightly longer extender to get from a 36 stem (or whatever the disk requires) to adequate clearance for the 80, but it's common.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [davetallo] [ In reply to ]
Quote | Reply
davetallo wrote:
You could get away with just one tube: stem length to match the disk, and if the 80 goes, just use the extender from the flat. you might need a slightly longer extender to get from a 36 stem (or whatever the disk requires) to adequate clearance for the 80, but it's common.

^^^^^This.

Also, many extenders have a threaded tip, so you can stack them to create a longer one.

https://www.slowtwitch.com/...t_Extender_stack.jpg

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
This is my setup. My only wheels for my TT bike are a disc/90mm. I use Silca latex tubes, because they have a short stem that works better with the disc. I and, I carry a spare extender if I get a front flat. I have never had a flat on my TT bike, so this is all theoretical. :)
Quote Reply
Re: Anybody riding a disc and 80 front all the time [ In reply to ]
Quote | Reply
Disc and 80 in the front all the time. Training or Race.
People ask me if I'm ok when it's windy, but it's safer than you think.
Most of all, it's fun to ride, so I go out and ride more often.
I highly recommend it.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [s13tx] [ In reply to ]
Quote | Reply
s13tx wrote:
Disc and 80 in the front all the time. Training or Race.
People ask me if I'm ok when it's windy, but it's safer than you think.
Most of all, it's fun to ride, so I go out and ride more often.
I highly recommend it.

Can you or anyone else give details on exactly what length tubes and extenders works for such a disc/80 setup? Would be super helpful, thanks.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [s13tx] [ In reply to ]
Quote | Reply
I was planning on a post today to share my experiences as a new rider on deep wheels. I'm waiting for my 80mm front to arrive so I borrowed my wife's 60 to get used to riding a deep front. I've been riding this 60/disc setup for about three rides.

Yesterday a front blew in, weather online said it was 20mph winds. It was definitely gusty. I completed a 60 minute interval workout where the intervals were roughly FTP. There were two times when I briefly thought a side gust was going to put me in the ditch. When the wind was on my side, I spent about half the time out of the aerobars. At 20+ and gusty, it was definitely slower for me to have the deep front. I would have been faster overall on a shallower front wheel. This is probably something I can overcome with more practice, but I'm not certain.

A previous ride was done at 16-18mph winds. It started out a little uncomfortable but I got used to it and by the end of the hour I was comfortable.

I'm definitely interested to experience the difference between a 60 and 80mm front.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
The valve length that you want for the rear disc wheel will depend on how much cutout space the wheel has. That said, latex tubes typically come with a 42mm valve, so that is probably what you would want to try first.

For an 80mm wheel, you would start with the 42mm valve on a latex tube and add an extender to get about 15mm outside of the rim so that your pump can get a good grip on it. Simple.
Last edited by: jimatbeyond: Apr 1, 21 8:46
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
s13tx wrote:
People ask me if I'm ok when it's windy, but it's safer than you think.
Most of all, it's fun to ride, so I go out and ride more often.
I highly recommend it.
This x10, for another reason... If you ride every day with the disc/90 combo, it becomes second nature. It really is not an issue in wind, but if there is wind on race day, it is not a thing for your mental game.
lightheir wrote:
Can you or anyone else give details on exactly what length tubes and extenders works for such a disc/80 setup? Would be super helpful, thanks.
I use tubes with 42mm stems for my disc wheels. It just works way easier to inflate. (I had 52mm stems, but that little bit made it a lot more difficult to position and secure the chuck.

I used the old Silca extender chart below to pick my extender length for my 90mm front wheel. I am using a 60mm extender for my front. You would probably need a 60mm extender for your 80 front if you use 42mm stems and a 45mm if you are using 52mm stems.


Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
I run a HED disk and 90 and just carry multiple tubes, as I have the space for them. Just so I don’t have to deal with swapping extenders in a race.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [exxxviii] [ In reply to ]
Quote | Reply
Thanks for that awesome chart - exactly what I was looking for, appreciated!

ST is awesome for getting detailed help on stuff like this. Kudos to all who have posted here, all the info is appreciated and bookmarked for future reference!
Quote Reply
Re: Anybody riding a disc and 80 front all the time [s13tx] [ In reply to ]
Quote | Reply
This! Ride like you race, race like you ride. Helps build the muscle memory for handling side winds and such.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [Craigfsl] [ In reply to ]
Quote | Reply
Craigfsl wrote:
I run a HED disk and 90 and just carry multiple tubes, as I have the space for them. Just so I don’t have to deal with swapping extenders in a race.



During a race, you can carry one tube with a valve extender installed that is long enough for the front wheel.

If you flat the rear wheel, remove the extender and install the tube.

I am just offering this information to people who don't have room to store more than one tube.
Last edited by: jimatbeyond: Apr 1, 21 9:11
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
I'm running a 60 in front and disc in back. No issues or problems. My disc is spoked, so no really worries about being able to true it. I recent converted both wheels to tubeless with no issues. Carrying darts and one spare tube (short stem with an adapter for use in front) as a back-up. The cut-out on my disc is big. With the short stem, I can get a regular pump head onto it with no problems. It's probably large enough to let me get a CO2 on with an 80mm stem, but I haven't bothered to try it since my current setup works for sure.

I know others see it differently and want to save their race wheels / tires, but I see no real issues with running this setup all the time.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
I'm fortunate enough to be able to own both a 90/disc setup and 60/60 setup where the 60/60 can run on either road or TT bike.

I will run a "mock" TT in training of a segment with the race setup often enough to handle it well. Suit up at lunch hour for 10-er. Or a weekend 25mi try. Something like that once or twice a month. Full race kit, helmet and all.

Otherwise I run the 60/60 simply as where I ride I don't care to have a rock ding up my disc. The TT segment I run are old tri or TT race courses usually, or organized by a local person into the sport. So less chance of an equipment damage trying out that "new" route.

Also, I do TT and not tri. But for training I have adorned the bike with more tri specific hydration simply for convenience and not needing to stop or change position to drink. Just sip from the straw and keep getting it.

Despite that not being "race like" my races are short enough I don't carry drink. So if it helps me train better........all for it.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [shotts] [ In reply to ]
Quote | Reply
My opinion: riding all the time with a disc is a bit much. I rather save it for race day, or pre-race test ride. Same goes for TT helmet, tri-suit.
I like to ``feel`` the added value of all of these items on race day, and sparing some wear & tear on expensive gear.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
lightheir wrote:
I’m finally getting a new tt bike yay me!

I already have a road bike so am planning to get a race ready tt bike with disc and 80mm front. I’m assuming I will need valve extender for the front and different tube stem sizes to accommodate both the front and disc as the disc likely needs a super short stem tube.

Any problems or things to worry about this sort of setup for training? Other than having to carry 2 different types of tubes?

What bike you getting?

Let food be thy medicine...
Quote Reply
Re: Anybody riding a disc and 80 front all the time [JackStraw13] [ In reply to ]
Quote | Reply
Honestly haven't decided yet - but I have a few in mind...
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
In theory would it not be more unsafe, only because you are always carrying more kinetic energy so if something happens, statistically your crash is worse since kinetic energy is proportional to the square of the velocity. So let's say someone is going 25kph, that person is carrying >50 percent more kinetic energy that is dissipated in a crash over someone riding at 20kph.

I'm not a fan of super fast set ups in training because its just spending more time going fast and it just makes the outcome worse if something bad happens. You can go do the same wattage and ride slower on slow tires, slow clothing, slow bike. Riding a slow set up in training also makes every uphill longer and it also means carrying less kinetic energy out of every downhill meaning less freewheeling and having to pedal earlier.

I prefer to go with slow set up in training, fast set up in racing. You don't need to ride fast race set up that often to get used to it, but maybe its because I have experience.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [devashish_paul] [ In reply to ]
Quote | Reply
The question of safety is an interesting one, because you're also assuming crashing into a solid object. What is the most likely scenario where you crash? Theoretically you're more safe moving faster if you're hit from behind by a car, reduces the relative velocity. You're also more safe moving faster if you slide out because the horizontal velocity vector is greater, causing you to slide more, which greatly reduces the force you experience. In practice I doubt there is a significant difference, and man it's a whole lot more fun riding fast gear than it is to ride slow gear.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [imswimmer328] [ In reply to ]
Quote | Reply
imswimmer328 wrote:
The question of safety is an interesting one, because you're also assuming crashing into a solid object. What is the most likely scenario where you crash? Theoretically you're more safe moving faster if you're hit from behind by a car, reduces the relative velocity. You're also more safe moving faster if you slide out because the horizontal velocity vector is greater, causing you to slide more, which greatly reduces the force you experience. In practice I doubt there is a significant difference, and man it's a whole lot more fun riding fast gear than it is to ride slow gear.

I totally get the thrill of riding fast, but I believe the reason we have speed limits on highways, is very simple. More kinetic energy makes crashes worse and there is always less margin of error at speed. Now this is a risk that is worth taking for the fun factor (if not we would all be riding fat bikes all the time in training in rode and TT positions). Just be aware that the faster the set up, the odds get worse in an accident.

Its also why XC skiers tend to prefer to train on slower roller skis and only use fast wheels for racing.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [devashish_paul] [ In reply to ]
Quote | Reply
Ha you're right about the physics, but for me, my average long training ride speed of 20-21mph may become like 22mph with a disc+80, which for me is completely outweighed by the fun factor of going faster!

I admit that I used to not 'mind' going slower in training - then I took the plunge and bought race wheels for my bike. Hate to admit it, but it made a real, obvious difference over a 2 hr ride. Then I started noticing that even the clothing I wore made a noticeable difference. I'm not aero weenie, but it's hard to give up like 8-10 minutes of speed over a 2 hr ride once you're used to it!
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
The reason I tend to use slower wheels/tires for training is a bit more practical.

One reason is that for racing I like to run the fastest tires possible with latex tubes. These tires will be a bit less durable than what I prefer for training.

This also means that for a race I will have fresh tubes and tires that I have had at least a couple of test rides on. This is true for a whole season, even if I race a lot and have a good number of test rides.

It is generally NOT a good answer to just say you will just put on fresh rubber right before a race. Installation errors are easy, especially for latex tubes and often it takes a test ride or 2 to make sure everything was done properly.

It is a myth that all those exploding tires you hear in T1 are from the sun heating up the air in tires, the pressure changes are just not enough. Those blowouts are mostly from installation errors in tires and tubes changed right before the race.
Quote Reply
Re: Anybody riding a disc and 80 front all the time [lightheir] [ In reply to ]
Quote | Reply
lightheir wrote:
Ha you're right about the physics, but for me, my average long training ride speed of 20-21mph may become like 22mph with a disc+80, which for me is completely outweighed by the fun factor of going faster!

I admit that I used to not 'mind' going slower in training - then I took the plunge and bought race wheels for my bike. Hate to admit it, but it made a real, obvious difference over a 2 hr ride. Then I started noticing that even the clothing I wore made a noticeable difference. I'm not aero weenie, but it's hard to give up like 8-10 minutes of speed over a 2 hr ride once you're used to it!

I totally agree about using faster gear in training being more fun. I generally like to run in the lightest running shoes my fitness will allow and in the pool, I will often put on an old racing suit if I want to do a benchmark set and see how fast I can get. Heck I even keep my legs shaved down, because its less drag in the water (keeping rest of body shaved down is a pain, so only do it for swim racing). I like pulling out my bike race gear for personal TT's and put on a fast helmet and tight clothing. I just concede on those days, I am riding with slightly higher risk (which is worth the reward)
Quote Reply
Re: Anybody riding a disc and 80 front all the time [devashish_paul] [ In reply to ]
Quote | Reply
Yes, I'll admit that nowadays, being 45+, even though I'm trying to absolutely squeeze out what performance I can get from my schedule and life without imbalancing it all, the fun factor is a near-top priority. I no longer intentionally do suckfest workouts like 2 hrs on a trainer staring at a wall, or running in the dark and cold late at night or ridiculously early in the morning.

And if I'm having a good time, I'll screw up whatever workout I have planned to enjoy it! (Doesn't happen too often.)

I've also finally hit that inflection point in life where I actually have real disposable income. Felt like it literally would never happen, but I guess if you work hard, save as much as possible, it'll all work out eventually. So I am definitely going to use the nice stuff I buy. Here in Norcal, there's nothing weird on weekend rides with using full TT gear. In fact, if you're a decently fast triathlete, it looks appropriate as you'll be blowing by 99% of everyone out there often at twice their speed, so might as well look good while doing it!
Quote Reply

Prev Next