DooDer

Dear Carol,

Glad to read that you are on the mend; Endos do damage.

I think that your main problem is going from one bike to another with different brake settings.
It could be that the bike you wrecked on did not have a firm adjustment on the rear brake
and was really not assisting in the slowdown: Subsequently, more pressure was applied
unconsciencely to front and it locked.

A technique which I've always used which may help in the future is to use two fingers on the rear
brake lever and only one finger on the front lever. On my bike setup it also helps that I'm running
Avid levers with adjustible fucrum settings so I can modulate brake pressures mechanically.

Do hope that this helps.

Duane

John E

Best wishes for a rapid recovery, Carol. It doesn't sound as though you were descending a steep hill, but doing so would also increase your chances of flipping over the front wheel. A friend of mine did just that and never did figure out exactly what happened, although I strongly suspect he braked too hard in front without straightening his arms and pushing himself back in the saddle. Using both brakes (or, on dry pavement, just the front) is proper technique. The folks who normally use only the back brake get themselves in touble either through inadequate braking power or by flipping when they panic stop with the (unfamiliar)front brake.

DannoXYZ 

Carol, glad to hear you're recovering well and have a good attitude about this. You'll feel much better in a little while. From looking at the pictures, you've got cantilever brakes on your bike. They look like this:


The brake cable pulls on the crossover cable and both arms push the pads onto the rim. Disc brakes are similar to what you find on motorcycles and cars. The have a "disc" attached to the center-hub of the wheel and uses a caliper that's attached to a stationary bracket. Disc brakes look like this:



There's various pros and cons of either system. They both work on resisting the wheel's spinning motion and creating a deceleration force at the contact-patch of the tyre. As you've noticed from your testing, there are various design factors such as leverage-ratio at the levers and pad-compounds that makes a difference in how much braking-force you have on the rim based upon a given squeeze on the levers. Ultimately, the upper-limit of braking force is how much grip you have at the front-tyre's contact patch on the ground. And in most cases, most people will end up doing an endo before overcoming the friction-limit of their front tyres.

robo

That sounds like a really horrible crash. I hope you can recover, and soon!

I think i may have an idea of what caused your crash, that others have not mentioned:

You have rim brakes (either V's or cantilevers), and not disc brakes, and said that the brakes appeared to work normally after the crash.

What can sometimes happen if the pad is badly adjusted on a rim brake so that it is too low, is that when you squeeze hard it can slip off the rim and down into the spokes. If the pad catches on a spoke, the bike will flip. This almost happened to me while demoing a bike at a shop, and i was furious, because the shop is downtown and i was riding around the block in traffic. If i had been unlucky, i could have died if i flipped in moving traffic. The shop was just really sloppy in setting up its bikes.

Anyway, if this was what happened, it would be quite possible that the pad would have popped back out to a normal looking position due to the impact, and under moderate squeezing of the brake lever would look like it was working OK.


This is just a guess, but i seems really strange that a normally functioning front brake would flip you that unexpectedly, especially a rim brake, assuming you weren't already angled forward, and then really gave the lever an abrupt, hard, squeeze...

Karldar

I can't see that happening with V's(not parallel-push, anyway), but I've had it happen with canti's before. Never actually got into the spokes, but it did dive below the braking surface of the rim.

cfm

Robo & Karldar,

You have presented yet another possibility that I find quite scary! IF this were the case with my bike brake pads, then HOW WOULD I BE ABLE TO TELL, since the brake pads appear to be in the correct position on the rims -post wreck. Is there something I can try to see if the pads will slip off the rim, other than getting on it, riding, and then braking hard (NOT!)? I will 'try' this afternoon to post a picture or two of the brakes and pads on the wrecked bike. Thanks for the new possibility... Yikes!

Carol

cfm

Duane,

I'm getting closer and closer to coming to this same conclusion. The rear brake seems to be much weaker than it should be. It takes a LOT of pressure on the lever for it to work as it should (?). With mild pressure on the brake lever the wheel keeps spinning with less resistance then seems normal. Regardless, I'm bummed at myself for assuming that this bike would be exactly (or mega similar to) the same as the newer 2005 version (same bike, model, etc.). They are in fact quite different regarding the shifters & brakes. The shifter difference was quite obvious. I should have payed(?) much more attention to the differences between the brakes. Your explanation makes so much sense (as do 2 other explanations), especially since my first thought/instinct (before these other possibilities were presented to me) was that the front brake locked on the wheel. I'll definitely put to use your one-finger on the front brake/two-fingers on the rear brake technique, at least on this particular bike! Thanks so much for the help! I really, really appreciate it!

Sincerely,
Carol... who's heading off into the land of Hydrocodone...

Karldar

Pics would be helpful, but don't cut your sweet dreams short for that. I'm sure that we can speculate indefinitely while you drift about in a pharmaceutical haze....

Maybe your husband could try the brake(without riding the bike). Just get him to give the lever a good, hard squeeze and keep an eye on where/how the pads contact the rim. If you have cantilever brakes, the arm, and therefore shoe/pad, will describe an arc as it is pulled toward the rim. If they're far enough away from the rim, they could arc in below the braking surface of the rim. V-brakes have fairly straight arms and describe a more shallow arc toward the rim(typically) compared to canti's. DannoXYZ's first photo is a good reference, though that particular setup wouldn't allow for much travel before the brakes engage(a good thing).

cfm

Here are a few pix of the brakes in question. Sorry the pix came out kind of dark in spite of the flash. I don't know if you can tell much other than what type of brakes they are... Would closer-up pix be more helpful? It would be nice to get a good, clear pic like Danno's pix (very nice!)...

Karldar

Those are V-brakes, cfm. If the pads fully contact the rim's braking surface after the crash, then I doubt the shoe/pad in the spokes was the culprit. I'm leaning more toward the difference in the two bikes and their brakes being the deciding factor, along with the road defects, than anything else suggested thus far.

Hope you're feeling a little better. Good luck with your recovery.

meatwad

Ouch sorry to hear that. Sorry to say but it probably was rider inexperience. Do incorperate the tips mentioned. There are a few mechanical possibilites that I can think of that might have contributed though unlikely.

One would be something on the front pads or rims that got suddenly rubbed off. Two that the rear brake cable wasn't tightened down enough and slipped during overzellous braking.

cfm

Yes, unlikely...


One: possible because I have a 6-yr old that loves to mess with my bikes when I'm not looking like turning or clicking the gears, tieing(sp) yo yo strings around things, etc., etc., etc. The bikes are in the living room. Unlikely though that she would have put something under one of the pads, even though she's done a few other bizarre things to my bikes...
Two: The rear brake definitely needed some adjusting because it was not grabbing nearly enough IMO. I know the front brake is the stronger brake, but the rear brake was just too weak. I have no idea if it had anything to do with the cable...


It looks like we've ruled out nearly everything except rider inexperience, the biggest factor being that I wasn't used to the bike that I wrecked (much stronger front brakes then the bike I was used to riding). I used to ride a huge 10-speed bike (was given to me) for years and never had a fall. I used to do some distances on it too. I don't remember it having a front brake, but I don't remember a lot of things these days. It's a real bummer to me to think that I was the culprit in doing this to myself! Humor is the best medicine though, and I will go on riding, and riding, and riding, that is with a little braking practice in there somewhere...

Thanks for the help!
Carol

cfm

Karldar and others who have been so helpful,

I broke down and took the bike to a shop in Laredo (Pro Bike) yesterday. I just couldn't wait the weeks it would have taken to take the bike all the way to Corpus Christi to the mega shop (The Pedal). I had one of the more experienced guys come from the back of the shop so I could explain to him what happened, etc. He immediately ruled out that the front tire would have been slightly airborn when I braked, thus me coming down on a stopped tire and flipping. He said, 'You're not a crazy rider are you?' I think I must be looking older (at 48!) and he just couldn't fathom me flying down the road having a blast... Lol! He looked at the brakes and said they looked fine and didn't even need any adjustment, then said wait I could center them a little for you. Then I told him about the rear brake being way too weak, and of course he reminded me that the front brake was the stronger brake, and I told him that I knew that (now... Lol), but the rear brake was really, really weak. He adjusted both brakes on the spot, but really thought that they were fine other than not being centered around the front tire. I suspect that when someone (like me) brings a bike into a shop that's not one of the 'good' bikes (Trek, Raleigh, etc.), then they really don't try to do a whole lot because they know these types of bikes have lower-end components on them (likely the case with my bike), etc. I wish they would just tell you that though instead of just being 'nice' about the situation they're facing with adjustments/repairs. Although they appreciate the business, I don't really think they like fooling with lower-end bikes. Last time I was there though, the same guy told me that my bike was a real 'good' bike, even though it has a 'Made in China' sticker on the frame. I believe GT's are owned by Pacific Cycle Works out of Southern CA now...

Anyway, I left both bikes (wrecked one & 2005 one) to have heavier tubes & gel put in all 4 tires because we have so many mesquite and cactus thorns where I live, and because the nearest shop is 60 miles away. My little hand pump doesn't do any good with with a punctured tube. He called me on the Cell and said that the shifters needed adjusting on the 2005, and other than that, the bikes were good to go. Sooo, the brakes are what they are... different on each bike! I WILL be practicing! I think Duane and others' explanations that the front brake locked (my 1st instinct) after being pulled too hard is what happened now, although it's still hard for me to accept (it's sinking in though). I took the wrecked guy for a short spin when I got home and it felt awesome as usual. I really like the feel of these particular bikes! Didn't go ride though because it was still 100 degrees at 9pm. It was 104 at 11:30 this morning so won't likely ride today either. Will likely reach about 115 today...

When I picked up the bikes I noticed an awesome Raleigh on my way out the door. It had an 18" frame (the size I prefer), was a plain-Jane other than being a dark-aqua color, and a $299 price sticker on it! I can't remember exactly which model/type Raleigh it was, but it would likely have been in my living room now had I perused the higher-end bikes in the first place. I really do like my bikes though, don't get me wrong. I just didn't realize that I could have gotten a much higher-quality bike in the price range I looking at when purchasing....

Again, thank you everyone for being so helpful! I really like this message board and will likely be reading it on a daily basis now! I've learned so much in just a few days of reading on here. Those who take the time to help others are so appreciated!

Thanks again,
Carol

dannyg1 

Here's a few ideas that haven't been covered:

Check the front suspension for proper function. It's possible that it could dive under braking and lock the wheel by hitting it under panic conditions, were it adjusted really loosely (there's a dirt mark smack in the middle of your fork, in your photos).

Check your hubs for really horrible side to side play. Braking with a maladjusted hub could cause severe instability.

Check your quick release or axle nuts for proper tension. If you'd left them loose, your wheel coild've dived to the side of the fork and locked.

Check your headset for looseness. Arc the bike forward and then brake, while standing off the bike and beside it. Do this at varying speeds and see if anything odd happens.

Your accident was scary and I'm sorry to read of it. Be careful out there! (this comes from a guy whom almost killed himself by riding in Manhattan streets, at night and in traffic, whilst locked into both cleats and having to panic stop. One of these days it will occur to my happy-go-lucky self that it's a good idea to release a cleat before coming close to a full stop...)

Danny