I want to purchase a nice road bike for commuting maybe around $2500, unfortunately my work doesn't have a indoor storage area. The bike rack is shaded (except maybe the handlebar area getting sun during certain part of day and possible rain). Would this degrade the bike and the components of doing this 5 days a week 8-9 hours a day?
Commute distance is about 12 miles both ways. Bike is stored in my living room otherwise.
Even if the rack wasn't shaded, the sun is really the least of your concerns when parking at a bike rack.
You don't mention what's providing the shade. If it's shaded by trees, fallen branches, dripping sap, and bird droppings will all be a concern. If it's shaded by a man-made structure, you might still have bird droppings. If you do, it'll be a lot.
As far as weather concerns go, precipitation is a bigger concern. Even if's covered, the wind will blow bad weather in. Water is, of course, hard on bikes.
Locking your bike up and taking it off of a rack is harder on it than you might expect. You'll end up scratching and dinging up the paint when you rest it against the rack, as well as locking and unlocking it. Since you'll likely attach the lock the same way in the same spot, it'll also rub off the paint where it contacts the bike over time. You can alleviate some of this by being super careful, perhaps carrying a towel or something to use as padding. But accidents will eventually happen.
Unfortunately, no matter how careful you are, some of your fellow commuters inevitably won't be. If the rack ever fills up, people will be trying to squeeze their bikes in, bumping and scraping every bike around them, yours included.
Finally, thieves will be a large concern as well. If they're looking at a rack and your bike costs 5-10 times as much as any other bike at the rack, which one do you think they'll steal?
If you're absolutely insistent on spending a chunk of change on your commuter, get one with a boring paint job, a belt drive, and an internally geared hub (or a single speed, if doable in your area). The belt drive and internally geared hub will alleviate some of the precipitation concerns, but not all. The boring paint job will make your fancy bike less obvious to thieves. You'll still get plenty of scratches and dings from the rack and other commuters. You'll still have precipitation concerns with other moving parts. And bike thieves might still steal it.
Alternatively, get a beater bike and don't worry about any of that stuff too much.
It’s not really a problem with quality components.
Some plastics can get brittle or yellow (e.g. those plastic covers and transparent „window” on cheap Shimano shifters) under UV exposure. Rubber will degrade faster.
I’ve had my Shimano 105 equipped bike outside for years in Austria and it didn’t suffer any damage. But there is not much exposed plastic to begin with. I think the frame’s white paint used to be whiter when it was new, but maybe it’s just dirty now. The rubber cover over the brifters got soft and stains my hands black, but I think it tends to do that anyway. The decal stickers on the front fork got brittle and ugly.
I’ve never had any issue with premature cracks in cable housing, saddle or tyres.
My mum’s Shimano Deore equipped trekking bike is also doing fine.
First off, I’m going to assume that your willingness to leave a $2500 bike outside stems from proper safety/security, ie you work in a gated complex or you live in a country where bike theft isn’t a big problem. Therefore, the only possible problem is that the rubber components will degrade as already detailed, and that the paint will fade. Paint chips and scratches can be minimized through the use of frame protection tape. $30-40 worth will cover your entire frame and leave you with extra to double-wrap high-contact areas or replace scratched sections as needed.
Riding the bike will be awesome, enjoy!
Harsh sunlight of course degrades plastic and rubber, and yes, rain will not be good for your components and bearings.
That said, it's a minor problem. These parts wear out anyway. You can replace them. If riding your nice bike to work puts a spring in your step it's worth replacing the bar-tape, brake hoods and servicing the bike a little more frequently. You probably won't even notice the extra maintenance.
If your saddle has a chance of getting exposed to water, it's a good idea to cover it with something.
Since you didn't mention security, I think it's fair to assume that security is not an issue.
Please consider if a $2500 bike for 12 miles is worth it. And especially a used one. Used bikes are good and they need to be taken off the market as well.
Buying a much cheaper one made for example for bikepacking and trekking, might improve comfort while decreasing the chance of damage due to storing in semi-proper conditions, as bikepacking and trekking bikes are made for all-weather conditions. Moreover, a belt drive bike like those made by Priority Cycles, a Cube Editor, a Cannondale Bad Boy or a BMC Alpenchallenge AC01 or AC02 (both the belt versions) will definitely help you lower maintain while decreasing the chances of the weather to affect your drivetrain, as belts and be cleaned with just a hose.
Which part of the world are you located? The sun in Copenaghen is slightly different than the sun in Miami.
If you buy such an expensive bike, it makes sense to maintain it properly ---> a good maintenance schedule will prevent or at least mitigate any damage to the bike sitting partially exposed to the elements for ~200 days a year.
For example: water infiltrating the steerer may be an issue (with steel), but with an expensive bike it makes sense to check the greasing of the fork every 3/6 months, so you have an idea about how it goes. Ditto for wheels'bearings.
I'd say stock up on compatible replacement brake lever hoods and store those replacement hoods away from sunlight. My experience is that storing a bike 24/7 outdoors in sunlight in latitudes where sun shines 16 hours a day in summer degrades the brake lever hoods in about a year or two. The failure mode is that they become uncomfortably sticky. If you do it only 5 days a week for 8-9 hours a day, then that's only little over third of the sun damage that 16 hours of sunlight every day causes. Besides, if the area is semi-shaded, it helps a lot.
It's not the end of life if your hoods degrade. Replacement hoods generally cost from 5 to 10 euros. It's not a big loss even if you have to replace your hoods in every second year.
The tires and brake pads though can take the sunlight.
The sun damages Everything but the bike will probably get stolen before the sun damage becomes noticeable.
Riding your bike indoors on a trainer is worse for your bike than leaving it outdoors.
Just make sure you do these three things, in order of importance...
