[Event] Cape Town Cycle Tour 2019

[Karooryder]

A few pages back we were discussing the crash where the rider's bike frame snapped - assumedly the result of wear and tear and then a rough road service on the route.

 

This got me thinking and I have a question to the technically informed:

Is there any way (which is obviously non-intrusive and would not cost an arm and a leg) to check for minute cracks / weak points on the frame of an older bike as a precaution?

 

My carbon ride is over 5 years old and has - for all practical reasons - driven halfway around the earth. I would not want to be the one to have a cracked frame fail at 60km/h. Thanks guys!     

Edited March 13, 2019 by Karooryder

[Skubarra]

1.03

 

 

(seeding is out)

 

Makes sense, given that the winning time is about the same as last year and the route is the "base" route.

 

Seeding computer doesn't care how the rest of us suffered, the fast pro's really messed things up for the rest of us 

[Zub]

1.03

 

 

(seeding is out)

 

I would love to know which of the following regression techniques they are using since 1.03 is definitely not linear when comparing difficulty to other events:

 

1. Linear Regression. The most widely known modeling technique.
2. Logistic Regression.
3. Polynomial Regression.
4. Stepwise Regression.
5. Ridge Regression.
6. Lasso Regression.
7. ElasticNet Regression.
8. BullCrap Regression.

[Long Wheel Base]

Makes sense, given that the winning time is about the same as last year and the route is the "base" route.

 

Seeding computer doesn't care how the rest of us suffered, the fast pro's really messed things up for the rest of us 

We used to have a race up on the highveld where the pros did a longer race that added a loop through suikerbosrand reserve. So the winning time for that race was always either a tandem, VA or VB. That was always a good one to get your seeding better.

[Karman de Lange]

 

I would love to know which of the following regression techniques they are using since 1.03 is definitely not linear when comparing difficulty to other events:

 

1. Linear Regression. The most widely known modeling technique.
2. Logistic Regression.
3. Polynomial Regression.
4. Stepwise Regression.
5. Ridge Regression.
6. Lasso Regression.
7. ElasticNet Regression.
8. BullCrap Regression.

 

 

something about the % of fast people that went slower than expected. 

 

The one tonner is nice example as most of the high seeding people fall back to ride with there DC team mates .. so  their final time is slower than  expected pushing the beta up.

 

Edit:  From website

 

 

• First, an extract is done of all the riders who did the event in question, as well as the base event. Every rider with an index better than 100 is taken for this calculation. The assumption is made that the same riders should have the same index for both events, so the winner’s time of the event is now adjusted and the “beta” is calculated to achieve this.
• In statistical terms, a linear regression is performed for the event relative to the indexes of the people in the event who also rode one of the base events. This determines how much the winner’s time should be adjusted and what the difficulty factor “beta” should be. There is no subjectivity in this process – it is an automated calculation without human intervention.

Edited March 13, 2019 by Karman de Lange

[LongDonkey]

How exactly does the 94.7 from last year get a 1.24 beta compared to the CTCT of 1.03?

[Capricorn]

A few pages back we were discussing the crash where the rider's bike frame snapped - assumedly the result of wear and tear and then a rough road service on the route.

 

This got me thinking and I have a question to the technically informed:

Is there any way (which is obviously non-intrusive and would not cost an arm and a leg) to check for minute cracks / weak points on the frame of an older bike as a precaution?

 

My carbon ride is over 5 years old and has - for all practical reasons - driven halfway around the earth. I would not want to be the one to have a cracked frame fail at 60km/h. Thanks guys!     

De-tect in Montague Gardens, Cape Town, offers various NDT methods, like x-rays and ultrasonics. They would be able to run some scans and given an indication if more intrusive inspections are required. You could also get a endo/boroscope to do an internal video inspection of high stress areas. But you need to be able to interpret what you are seeing correctly. I think de-tect can assist in that regard too.

 

By good design, and excluding impact/shock loadings, carbon composites won't fail suddenly without some warning that typically appears as paint cracking. Note: that's not to say all paint cracks are definitive proof that there is a developing failure in the carbon (or metal) underneath. But as visual inspections go, cracks in the paint are a starting point for further consideration.

[MudLark]

So, a few months back a mate of mine was riding a fairly new carbon frame mountain bike, the brand of which will for the time being at least, remain unstated. This was at Northern Farms. Towards the end of the ride, we noted that one of his chainstays was cracked, nearly all the way through. He had noticed nothing. If we had kept riding a bit longer, it's quite conceivable that this thing might have given in altogether on a long fast downhill – with potentially disastrous consequences. It happens.

[Spinnekop]

We used to have a race up on the highveld where the pros did a longer race that added a loop through suikerbosrand reserve. So the winning time for that race was always either a tandem, VA or VB. That was always a good one to get your seeding better.

I remember the 94.7 that had an extra loop for the Elites around Harties and Hekpoort.  200km for the day.

[matthieup]

Does anyone have actual figures regarding the wind speed on Sunday?

[Sbloomer]

Does anyone have actual figures regarding the wind speed on Sunday?

 

 

Observatory

Blue Route

Castle Rock

Noordhoek

Edited March 13, 2019 by Sbloomer

[Long Wheel Base]

I remember the 94.7 that had an extra loop for the Elites around Harties and Hekpoort.  200km for the day.

Sjoe I don't remember that. What years was that?

[Spinnekop]

Sjoe I don't remember that. What years was that?

Both in 2003 and 2004

[matthieup]

Observatory

Blue Route

Castle Rock

Noordhoek

 

Hi actually also found a archive section on windguru. Seems to indicate about 50km/h with gust up to 70 by Cape Point

[DieselnDust]

De-tect in Montague Gardens, Cape Town, offers various NDT methods, like x-rays and ultrasonics. They would be able to run some scans and given an indication if more intrusive inspections are required. You could also get a endo/boroscope to do an internal video inspection of high stress areas. But you need to be able to interpret what you are seeing correctly. I think de-tect can assist in that regard too.

 

By good design, and excluding impact/shock loadings, carbon composites won't fail suddenly without some warning that typically appears as paint cracking. Note: that's not to say all paint cracks are definitive proof that there is a developing failure in the carbon (or metal) underneath. But as visual inspections go, cracks in the paint are a starting point for further consideration.

 

 

thansk very much for this info. My next frame will be checked by them before I build up into a functioning bike. an Annual inspection thereafter may just save some skin.

[Mamil]

This seeding mularkey is interesting. My sub 3 99er gave me 17.31. My 3.31 argus gave me 31. I'm probably halfway between these two numbers... on a good day... with fresh legs...

 

I certainly couldn't have gone harder on the tour but i had something left after the 99er.

 

Supports the view that ppa members get inflated seeding. Wish they wouldn't do that.